Best way to Bridge?

I have a Netgear wnr3500 v1 (routing enabled) connected to a 2wire dsl modem (routing disabled) upstairs.  For downstairs in my garage i just purchased a Netgear wnr3500L.  I want to build a wireless bridge between the two. I want one as the base (primary) and one as the repeater (secondary).  Im not sure which one should be which?  Should i flash the 3500l with dd-wrt and use it upstairs and move the 3500 v1 downstairs or the other way around?  Can tomato or dd-wrt firmware adjust bandwidth coming from dsl?  Currently im only getting 1.5mb on the download with At&t DSL.  I realize the 3500 v1 is not flashable with open source.  My goal is to get the optimum download speeds fromt the internet on the computers i work on in the garage connected by wire from the secondary router.  Any help would be appreciated.