1996 Buick Century using coolant like crazy, smoking from hood?

I bought a 1996 Buick Century in a fit of desperation about January. Not too long after I got it, I noticed a funny smell. Well, that smell turned into smoke. Lots of smoke that comes from the hood of my car after it's been driven or when it idles for a little bit. Another thing I realized is that smell I mentioned earlier was anti-freeze/coolant. My car uses coolant like crazy (2-3+ bottles a week). One moron mechanic said it could be my head trying to blow. Another stated that the intake manifold was made out of plastic at that time and has most likely gone bad. What I'm wondering is how do I, myself, repair this as simply and as cheap as possible without furthering any damage? I just need this hunk of crap to last me until I can get a better job (hopefully before the beginning of May).