[Closed] Which replacement Bottom Bracket?.

Hi folks after last nights awesome Bike Chain ride up the Pentlands Ive discovered my Bottom bracket is kinda knackered . There is a lot of play coming from it especially when In the small ring. Now heres the spec for my bike .

[url= http://xrl.in/5p22 ]GT Aggressor XCR[/url]

Now going by the spec It says Its a Truvativ Firex 3.1 chainset with GXP BB , Being a bit of a plumb and knowing very little about components is the GXP Bottom bracket bog standard or are there different sizes or specs.

I walked into halfords today and was served by a lad who looked around 12 who stared blankly at me . Please help .