What can I do about my stupid truck?!?

I've only had it for 2 years. It was used when I first got it. It's been giving me problems over the last two years. Recently though, the truck will begin to like jump/stutter/jerk when i get up to speeds between 30-50 mph and I hate that! And it's starting to turn off on me when I stop at a light or somewhere. It's a 2004 Chevy Avalanche. What should I do? I can't exchange it because I haven't had it for so long and don't have that much paid for it. So what else can I do? I've gone to get it repaired but the problem came back. Should I wait for it to completely mess up or try something else? Please help.