1994 Saturn SL1 Is it worth fixing?

I have a 1994 Saturn SL1, manual trasmission, that I have owned for about 2.5 years and am the 3rd owner. It have about 168000 miles on it
It has run great until recently. In the time I have had it I have only had to replace the tires, muffler and front brakes. The car also gets great MPG, 35-38 in the summer and about 30-32 in the winter.
The car has burned oil for as long as I have owned it, my husband checks it weekly and on average, with the amount of driving I do he adds about a quart and when he changes the oil every 3000 miles the oil is very dark. Like I said I still get good gas mileage and don't have a loss of power, easlily does 70 on the freeway. Do I need a new engine or?
Sencond of all I am having a hard time shifting, some times its fine and others I really have to muscle it into gear, more so when gearing down such as to get off the freeway, and when having to stop and start again. But again it is not a constant. I took it in and the mechanic thinks that is something with the connection of the clutch to the transmission but couldn't be more specific unless he could take the transmission out, to the tune of about $700.00, in labor costs alone.
I also have a rubbing noise on the front passengers side, most noticeble when I make a left turn. I also noticed when my husband was changing the oil that in places on the back side of that wheel there seems to some wear marks.
With all the problems that have come up recently I'm just not sure if the car is worth fixing.