Back up. There is no other real advice to give. All you can really do is back up. Hopefully your room sounds ok. Otherwise, you will just have to live with what you get. If you are serious about recording your singing, money might be better spent going to a decent project studio or an honest to goodness recording studio and have someone there push the buttons for you.

If that is not an option, you might just consider saving a bit more money and investing in some proper equipment and room treatment. It's hard to take short cuts and make things work. That's not to say it can't be done but it certainly is more difficult and if you're inexperienced to begin with it may seem impossible to get any decent quality.