Point 1: Trading a car in on a lease is a terrible idea. Go to the car purchasing forum for more info why (basically, you never want to put money down on a lease, and that's what you're doing with a trade).
Point 2: You don't want to be leasing a car in college. People will puke in it. People will spill stuff in it. You'll scrape up the interior loading it with crap. People will back in to you. You'll let someone borrow it and they'll let someone smoke in it and a cigarette will get burned in the back seat. You don't want to have to be worrying about these things. You don't want to have to not be able to take a road trip to Montreal or Sunday River because you'll go over your mileage for the month.
Point 3: Just because your jetta is in tough shape, doesn't mean all used cars in that price range are. For example, I've had my 03 civic si hatch since 03 and I haven't been able to justify getting rid of it for nearly 10 years. After warranty ended, it's needed tires, brakes, a tie rod end, and headlights. I change the oil with synthetic every 5000-7500. The only major repair is the AC compressor going, but I haven't even bothered to fix it yet.
Point 4: You're in college. SUV or hatchback is the way to go. I had a mk2 gti in college --- with the seats down, I could fit all of my stuff into it.
Point 4: So what do you do at the end of your 3 year lease? You're going into senior year, you'll probably have some credit card debt or student loan debt. Hopefully you won't have missed a payment or been late on one. You'll have no job and no income and zero cash to put towards a car. If your credit isn't perfect by then, you might have a tough time getting another lease. So what do you do?
My advice: Sell your jetta, buy a used civic (Si hatch like mine will run you probably $4k-$7k), don't worry about car payments, don't worry about voiding a lease, don't worry about what you'll be doing for a car your senior year when you're flat broke. At the very least, if you do lease, wait at least 3 months after you get to college --- see what it's like, see how tight money is, see how little time you have to work extra jobs, see how your car gets treated up there, etc, etc, etc. But don't get into a new lease before you go
