I did have similar problems with dropped connections earlier. That appeared to be due to problems between my router and DSL modem. Once the modem was in true bridge mode and the pppoe was being handled by the router, the problem went away. I do not know your network setup, but perhaps you are running more than one dhcp server or this is misconfigured. I use static ip on my network. You could try turning off the dhcp server on the router and and use static ip on the laptop.

There are also a number of threads regarding problems with various versions of the card - check with these. I think that there may have been a change in the chipset at one time. Perhaps another module is needed for support? Anyway, my identical laptop worked right out of the install after I did the steps outlined previously, before I messed with any of the modules or rebuilt the kernel.