You're not going to get anywhere unless you have a good A/D converter. I use a POD X3, which is good for usb recording and amp modeling. Mind you I'm not the best at mixing but this is where my gear gets me
The other way to go is to buy a really good instrument mic and something like an M-audio or Presonus interface.
After that you're going to learn how to mix and use tools like EQ and compression. You should be able to find plenty of online resources to help you with that stuff.