You can remove the tire from the rim yourself, but I recomemd you call a friend who is over 200lbs. it's a little laborous but easy to do, no need for special machines.

just deflate the tire, and you and a friend stand on the side wall to demount the bead, either the outside or inside will dismount easier. after breaking the bead, just slide the remaining tire over the lip of the rim (use soap and water to loosen things up if neccessary)

to install just reverse the whole procedure, again the tire will slip on easier from either the front or the back, be sure to pay attention to the tires rotational direction. I would only attempt one rim, if you need to do all 4 it's worthe the $40 they charge to use the manchine
http://www.xs11.com/faq/tirefaq.shtml