[Personal story section, skip down to next paragraph for the point]
I've never heard of anything like a rj45 to firewire adapter or cable, but that doesn't mean it isn't out there. The dorm rooms I moved into had rj11 network drops in the rooms so I went to the uber nerd local computer store that has a cable section the size of my house. The 3 guys there, who have worked in the industry since the days of trash 80s, had never heard of anyone using a setup like that. Ended up having to splice myself a cable instead of waiting the 2 weeks for new ones to arrive from god knows where.
The best place I've found for finding things like this out though is here
http://www.offspringtech.com/Data_Spring.htmlThey do custom jobs, so send them a message and see if they could do it. But they don't have anything like that listed on their site's catalog. You can get a working PC card for about 10 bucks including shipping online, might even get a better deal from clearance items locally too.
[Insulting shorty section]
And shorty, if you are stupid enough to buy trash equipment then you deserve it. Don't blame people for ripping people off who are too stupid to ask someone for help. Besides a 56.6 goes for like 5 bucks these days. Also, don't blame the computer for your idiocy.