Bikepedia has specs for your bike here: http://www.bikepedia.com/quickbike/B...acer&Type=bike

$70 sounds high for a BB replacement. Did the shop mention anything about your crankset being trashed?

First you have to find out whether it's the BB or the crankset. If there's a lot of play in the BB moving one of the crank arms will move the other as well. If only one arm has play in it chances are you messed up the square taper in the arm. To replace an arm you need a crank puller ($15-$20) plus the arm itself obviously. If the BB is trash but the crankset is fine you need the crank puller plus the appropriate BB tool (~$10) plus a new BB (~$20.)