So I am new to this, and I am bound to have a few more spills as I get more acquainted with cycling. The bike I bought is, based in most opinions, a pretty decent starter bike (and I got it for under $400) anyway its a RapidCycle Grand. The wheels on it are pretty crumby. The mechanic at my LBS said the nipples on the front wheel were too tight to adjust (granted he didn't try much). Anyway he said they were true enough. Well, after riding downhill at some higher speeds, I can feel every contour in the wheels. They are likely rebranded junk wheels. 700 x 40 with kenda 23 tires.

The tubes were popping when inflated to 90psi so I put some fabric liner in.

Anyway, I am new to this. I want to get all in because I can't do it another way. What should I do with these wheels? Run them till they can't keep going or should I upgrade (preferably to something reasonably priced)?

I'd like your opinions and advice. Also what's a good material, weight, spoke type/count for a commuter? Thanks in advance.