I wouldn't put any money into mining hardware if I were you. However, it's quite easy to make your own calculations. There are online "mining calculators" you can use if you want to. Also, keep in mind that people who are miners themselves are interested in keeping other people away from mining, since the mining difficulty (and thus, the mining profit) increases when more power is put into mining.
That's what I figured. I wish I had gotten on the mining bandwagon back when the system was new, and the profitability was higher. Based on some of the calculators I've toyed with, it would take me way too long to break even after buying new hardware, and I don't feel like blowing out my current rig for very little profit.