M-audio doesn't make the best stuff in the world but the Solo by itself shouldn't be making your stuff sound horrible. 
All kinds of other things come into play. What mic are you using? How do you have it placed for what instrument? pop filter for vocals? What kind of room? Any sound treatment for the room? How are your tracks being mixed?
Its usually NOT the gear that is the bottleneck for getting good sound. When the gear does become the bottleneck you'll have enough experience to know what you need to make it sound better. 
For now its probably your technique that needs work- and there is no magic bullet for that. Lots of reading and lots of experimentation. 
have fun!
Chris