I agree with your sentence here - "Evolution didn't share my goals, and didn't optimise for my environment." We are going to be seriously suboptimal at living in cities.

There's also no shortage of articles about improved intelligence. For example.... http://scienceblogs.com/cortex/2009/10/smart_mice.php

Here's the problem. Most of these mutations are actually pretty easy mutations. They will occur naturally. The systems the mutations act on are also venerable - we share these systems with mice for the most part even though we haven't had a common ancestor in absolutely ages. The inescapable conclusion is that evolution has tried most if not all of these mutations already, and threw them out. Why would that happen when intelligence has such an advantage? We don't know - however I think we can consider it almost statistically inevitable that it must have happened on quite a few occasions.

All I'm saying is this - we don't know why evolution threw these things out. There must be a reason, and that reason may imply that it's not advisable for you or I to mimic the effect.

There is a flip side - maybe evolution really hasn't optimised this correctly - selectively speaking we're largely cavemen with a bit of farmer thrown in. Civilisation really hasn't been around long enough to make much difference.

So in summary - I think there is evidence to suggest that you'll be able to change your brain function to enhance measured intelligence by taking certain substances. I also think that nearly all of these changes will correspond to changes that evolution has tried and has rejected - for reasons as yet unknown. Your call.