A gear puller may work, they usually destroy the crank but I guess since it is bent this will not be issue, unless you are going to try and straighten it?
To get the crank off in one piece, you need a proper crank extractor. This screws in to the threads on the crank, and then pushes it of the axle. Here is the park version -
http://www.parktool.com/tools/CWP_6.shtml,
but you can probably get a much cheaper unbranded version from your friendly local bike shop.
Hope that helps
Edit: Unless you are going to be using a crank extractor regularly (not very likely I would guess), probably your best option is just take the bike to a local bike shop and get them to take it off. They will probably only charge you a few bucks, might even do it for free if you buy a new part from them!