I can't really promise buying a pre can 100% solve your problem, I just based on my experience.
I've tried M-Audio Fastrack pro and my friend's M-Box, both of them need to crank the input gain till around 2 o'clock or more to get a good recording volume. It's even worse with dynamic mics like SM-57, I must crank it up till almost 10 to get a good recording volume, and then I've do some research, post question at both website support forum, but many people got same issue.
After I buy a mic pre (not because of this problem, just wanna upgrade my gear), I just need to turn my gain around 10-11 o'clock and the input level is good.
When you crank the input gain, you will hear some hiss (air sound), but I'm not sure if that is your only problem.
If you can borrow a mic pre to test it, you can see if its really like what I said, or its becuz of your mic.