recommendation of a sound level meter

I currently have a pair of Quad 988 loudspeakers, Thor Audio TP 60 monoblocks, Thor TP 2000 preamplifier and a
Cary 306/200 CD player. I am attempting to cure the
problem areas in my listening room. At this point I am not really sure what they are. It was recommended that I purchase a sound level meter to help me. Can anyone recommend a sound level meter besides Radio Shack that is
very accurate and reasonably cost effective. Thank you for any light that you can shed.