double wireless connection?

I'm new to linux, (6 days now) and have been using XP on my laptop and my wifes desktop. I have a dell inspiron 5100 with a mini-pci 1450 a/b/g wireless card on the inside and an pcmica linksys wireless g. the router is a linksys wireless g. from within XP our computers are networked together.
now the first time i tried mepis i couldnt get the internet to work, i think the router is set to only do wireless g conections and ignore b. which i believe the mini-pci is running at in mepis. but my neighbor has a wireless b and i can connect to him with just the mini-pci card, but when i slap in the pcmcia card, bam i'm at 54mbps. em i connected to both my network and my neighbors? and also if I am, I have mine on an encryption that i havent setup in mepis. can mepis bypass this because the routers encryption is set for windows?
oh and how do i set mepis to be apart of an encrypted network (one that shares with XP)?
I love mepis and will be completely moving my laptop over to it but theres a few ??? i have before I remove XP.
thanks
me