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Hopefully you have a set of vernier calipers in there, you can use that to measure the BB shell, invest in a BB puller like a Park CCP-22 http://www.parktool.com/product/cran...-cranks-ccp-22 once you have pulled the crank, you can measure the spindle length (it's more user friendly than the Niagara one you linked to, any good LBS should stock Park Tools)

Check out the Park Tools site for repair help,

For BB's http://www.parktool.com/blog/repair-...racket-service

For Cranks http://www.parktool.com/blog/repair-...e-spindle-type