Trouble starting/stalling

I bought this car from from my cousin who knows nothing about cars. She stopped driving it because it overheated. So I bought it, and found out the hose closest to the window was leaking coolant, so I replaced that with a new hose, drained the radiator, and then put new coolant in. It then worked from the 8th until Friday the 1st, it started to overheat. So I then notice that my coolant t-tank (overflow) where the cap is has been melted and the part of cap where hose goes from there to radiator was broken and no longer attached. And that there isn't a hose going inside the coolant tank. So I get a new coolant cap, and a hose for inside of it and connected the hose to the new cap leading to radiator. As well, as replacing the thermostat. I then, drain radiator, and fill the radiator (where metal cap is) with coolant until I see fluid. I let my car run for a minute to let it circulate. After a couple minutes, I then pour more coolant in the radiator cap and then I fill the coolant t-tank with coolant up to the full line. Let my car circulate, and then I have to fill the t-tank up a little more. After this, my heat started working, car wasn't overheating etc. Driving just fine for my 50 minute drive, and I let: the car sit for about an hour or so. I then drive 10 minutes down the road to the store and when. I get done with the store I go back to my car and when starting it, it has a little trouble starting but does. At: that point it slightly sounded like it was going to stall, so I rev the engine up, thinking it maybe because it's so cold, and then go on with driving. I get back to the house and after 20 minutes of letting it cool down, I check my t-tank and it's completely emptied. So i'm thinking the engine didn't get enough coolant to stay circulated or whatever, so I then fill the radiator with more coolant until I see fluid, and then fill the t-tank up until the full line. During all of this, i'm checking for any leaks, none, and checked my oil- seemed a little low but couldn't really tell so I put more oil on, just a tad. Now i'm getting ready to drive somewhere else, has a little trouble starting but does and kinda spurts/jerk when I put it in drive and start going. After about 4 minutes it's fine. So, I wanted to make sure coolant level was good and oil, so 10 minutes into the drive I stop pull over, let it cool down and check my levels. Coolant tank is a little below full line, oil is good, so I put more coolant in the radiator spot. I try starting the car and it has a longer time starting, so I press the gas a little and it goes but it's jerking/sputtering I guess. While i'm driving down the highway, it starts to seem like it's having trouble going so I press the gas even more to try to keep it started and couple mins later I get to a stop sign, and when I try to go my car stalls in the middle of my turn. I was able to start the car again, but it took at least a minute to get it started while having to press the gas quite a bit to start, after that i'm steadily holding the car at 50 mph until I get back to where I was. I get there and when I come to a stop it stalls. So now, my car is midway in the garage, won't start. Now it will turn over, you hear it wanting to start but won't like it's too cold or something. Every time I try to start it and it won't, or when it does for 2 seconds, it shuts off and I hear boiling fluids like I did when the cap of the t-tank was slightly off because of it melting the ring on top of tank. Now, the cap is completely on the tank, coolant is in the tank, oil seems fine. I'm just trying to figure out what else to do. So when I look underneath my car there's 2 big pipes looks like coming from the engine where you fill oil at, is dripping midway underneath front of car. The liquid hitting the ground is a very light brown color, and couldn't really tell the smell. Any suggestions? Pictures attached are the old t-tank before replacement. The picture with 2 hoses, there was a tiny house underneath those that was replaced.