Hi, you should consider getting yourself an interface which will give you more control over the mic levels..
If you think you are gonna get serious about recording don't make the same mistake I made....
I bought cheap stuff and kept wondering why I had a rubbish sound..it sounds like you may be going down the same route, I think Boydie will agree that (if your gonna get serious) it's worth getting a Rode NT 1A and a reasonable priced interface from..maybe, Focusrite..everybody will have their own view on equipment..these are just some suggestions..
I spent a lot more money than these two items cost before I realised I would have saved a lot of money if I'd bought them straight away..just had nobody around to advise me...
good luck, Kevin