1994 Cav Z24 needs a new engine

First off, I purchased a 1994 Cavalier Z24 for $900 last year. The car has 170k miles on it and runs like crap. So I'm wondering, are there any websites that sell performance or economically designed engines made for my year and make? I'm looking to spend around 1-1.5k on the new engine. ANY help would be appreciated.

BTW,
I don't know much about cars, but we took it to a dude who fixes em for a living and he said that it is just gonna keep falling apart over the next few years... and our best bet was to buy a new one or yank it out of a junk yarded one (already checked, none around with the motor).

3.1L V6 Automatic

i say buy a new one, or not that new...a 94 seems old, it prob will keep falling apart. u say u'r willing to waste 1.5k, u could easily find a 96-99 with like 2k.

i was seeling mine a a couple of months ago for 3k its a 01 with 17's and 58k miles, then i got tired of trying to sell it and decided to keep it a little longer.