My 50mm f1.8.

So, I was playing with my new toy last night and trying to get some shots of our chrissy tree (for fun) there was low light and I was trying to add light with exposure compensation but it still came out a bit blurry coz the shutter speed wasnt quick enough. I was on Apperture setting of f1.8 (thinking this would allow more light to come in) but it wasnt doing what I thought it would do. i pumped up the ISO to 400 and 800 but still didnt make a difference. well, maybe a bit but not what I expected, What am i doing wrong?

i was hoping to use this lens when i go to gigs to get shots of bands ect with no flash.

Can someone please shed some "light" on this for me (scuse the pun LOL)

and also any other tips on getting the most out of this lens would be FABULOUS
Cheers