That's a tough one. It's hard to say no if you've got the bug. If I were in your shoes i'd wait till i found a really nice 318 for a good price. It can be tricky, because if you get a problem child, kiss your time and money goodbye. I'd wait for something with low mileage though, nothing above 100-110k. I spent a couple of months shopping and reading this forum before I got my 92 325i with 80K miles. It had a few minor bugs, but i'm working them out. Read online here for buying tips on what to look for and things to check (like what kind of condition the shocks are in, the sunroof, interior, whatever).
Other than that, best of luck.
Cheers - Nate
Wherever you go, there you are.