Hydraulic clutch repair- save me!

There is some, "overlap" for labor if you fix the rear main seal when the clutch is replaced.

However, I am wondering about the, "broke" loose and the pedal went to the floor. Am I correct in that the pedal went to the floor?
If so, how did you get it to work again? Did it just come back up?

The reason I ask is that there is probably more damage or the reason the cutch is slipping is different than the rear main seal leak.
If the pedal went to the floor and came back, how did it feel when you shifted it or put it in gear?

If the pedal went to the floor there was either a failure with the hydraulics that make up the clutch pedal which disengages the clutch so you can shift it and take of from a stand still without stalling it. This system is very close to your brakes. There is a master cylinder that is full of brake fluid, the same fluid used in brakes, which pushes fluid when, you press the clutch pedal, to a slave cylinder which pushes the throw out bearings that push the pressure plate that, "un-clamps" the clutch so you can shift, put it in neutral, etc. If the pedal went to the floor, there is a failure somewhere in the clutch hydraulic system. There is either air in the lines or a leak in the master cylinder, hose or slave cylinder, or maybe the throwout bearings or pressure plate.
My guess is that there is something wrong with the aforementioned clutch hydraulics or pressure plate that lead to the clutch slipping. There is definitely something wrong with that system and if you are sure that the leaking fluid is oil, then the rear main could have started the slipping.

Either way, The clutch repair would include the following parts;

Pressure plate and clutch disk
Pilot and throw out bearings, (generally the pressure plate, disk and bearings are sold as a kit)
Flywheel, (since the clutch has been slipping it needs replacement. Don't let someone talk you into re-surfacing it as there are so thin that they are usually replaced in a case like yours as the heat from slipping it has created deep cracks that will cause your new clutch to have problems. You can also find clutch kits that include a flywheel as well as the clutch components in one kit).

With the mileage on your car and the description of issues, I would suggest replacing the entire hydraulic system for the clutch, I replaced the system on my Integra for under $200.00. I did not use OEM parts, do not by EBay stuff. I bought everything through Summit Racing, Rock Auto Parts and US Auto Parts. However the site has links to aftermarket parts dealers who are reputable.

You will need the following to replace the hydraulic system for the clutch;

Brake fluid
Master Cylinder
Clutch Hose
Slave cylinder

You will also need to check your transmission to make sure it is ok.

As far as the leak on the timing chain cover, that can wait unless you have never changed the timing chain. I don't have a service manual for your car, but it could have a timing belt. If that is the case and it has never been replaced, that is very important to do. I will try to find out if you have a timing chain or belt.
If you know and have never serviced it, let me know so we can focus on the clutch issue.

I also really like the Maximas before the 2003 model. I had a 2002 Altima 3.5 and the Maxima still had the older body style at that time. I really wanted the Maxima, but could not afford it.

As overwhelmingas it seems, it is worth doing things right if you really like the car and want to keep it. As far as repairing just what it needs instead of everything I listed, the hydraulic system will have to be looked at by a mechanic in order to see what needs replacement.
The clutch components are all necessary. If someone tries to talk you into re-surfacing the fly wheel, keep looking for a complete clutch kit with flywheel and all the other components. Also this sight has links that will help you find a reputable repair shop in your area.

The main seal is pretty easy to do if the cutch is being done. It should only add an hour or so of labor to the clutch job and the seal itself should be less than $40 at most.

I know this is probably overwhelming and maybe not what you want to hear. I am not trying to steer you towards spending more money than you need to or anything like that. There is only one way to do mechanical repairs, the right way. My 1990 Integra is in my garage right now waiting ubtil I have money for a new radiator. But it is worth it because I won't have to worry about it if I do things the right way.
You have to weigh the pros and cons and your desire to keep the car.

I hope this information helps. I will keep an eye on this post for your reply and get back to you ASAP. I am here to help and will do everything I can to get through this issue.

Honestly it is starting to sound like a money pit.
However, when looking for a good mechanic, see how clean there shop is. Does it look like they have ancient diagnostic equipment? Do the employees where t-shirtsd and jeans or uniforms?
Kinda like going to a restaurant, would you want your car to, "eat there".
You can also check into JDM, (Jampanese Domestic Market) places. You caan get parts with 30,000 miles for a good price and shipped. There is a law in japan where they have to get a new motor or car. The cars are so cheap there, most get a car.

If the clutch is slipping, either it is worn, the pressure plate is bad, or it is covered with oil (as mentioned). I don't know where the leaks are located, so I can't give you a price or determine if that is the problem. The only thing you can do is remove it and check to see the cause. If the pedal is going to the floor with no resistance, then you most likely have a slave cylinder or clutch master cylinder that is bad. Make sure the fluid is full.