Expert help please

I've a small room with some probs I would like to pick knowledgeable brains about. It's two layers of gyprock (9mm and 13mm) [about 5/12th " and 1/2 "] Dimensions are 12'6" x 10' 10" x 6'6" walls sloping up to a roof peak of 8'4". I've got rigid fibreglass (3" 48kgm3) 2'wide floor to ceiling across front corners , a 2' x 4' piece on 1st ref points on walls , (2) 2'x 4' on the back wall and a ceiling cloud of 4' x 8' taking in 1st ref points. Where should I go from here as it still sounds very average and is there a theoretical best position for monitors (Event ASP8s) in this room ? Sorry for the mixed metric/imperial - Thanks in anticipation, cheers Ross.

Sorry for the delay, summer projects an' all - Have you seen this? http://www.johnlsayers.com/phpBB2/viewtopic.php?p=18059 If it's not enough, just yell... Steve