Can you say, "SM58"? That is a good start. Can you spend more? OK, A SM7b. Hang blankets (Like those padded moving blankets) around the vocalist kinda like a tent. Use boom stands to suspend the blankets. This will help kill "flutter echo" from the room reflections entering the mic. Is the singer overdubbing, as opposed to singing "live" with the band? Get a decent pair of "sealed" headphones for him/her. This will minimize leakage of sound from the phones back to the mic, which can cause feedback squealing. A touch of compression always helps keep the voice more consistent in the mix. And as for delay, stay away from long reverbs, but try a nice, clean delay at under 100 ms...experiment with the delay time vs the tempo, and print the delayed signal onto a seperate track from the original voice.

Thanks, yea, hes singing over the instrumental track. But i dont know how to set this all up with what i have. Garageband is fairly limited, so. If i have the Instrumental track in garageband and hit play/record then the instrumental track gets re'recorded into the vocal track. Do you get what im saying? So can you give me options on how to do this?

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Honestly, i've never used Garageband...that re-recording scenario sounds pretty pointless...if that's what really happens, then the ppl who made Garageband must know something we dont (or most probably are retarded).
What I'd recommend is getting a Protools set up. Get a digi002 on ebay ($700-$1200 on average) and learn to use it. As for mics, quality mics are getting cheaper everyday. Try any condenser options from companies like Studio Projects, some MXL's, etc. Definitely try conditioning your room like moonbaby mentioned. And try overdubbing the vocals after you record a scratch track along with the band playing.