Using two ethernet ports won't make your internet go any faster. Your still capped at 1.5 MBS. As for lan parties, yes, using cat6 cable can make if go faster, but we are talking from 25 ping to 10 ping. Minute difference. Plus, one that cat6 goes through a slow router, you just wasted it because the router is slow.
Here is a speed test you can take (requires JAVA)
http://www.dslreports.com/stest?loc=97
And I would use 27563 as your Rwin. You are not pingable, so I took and average ping and used it. It shouldn't make a difference, but it will make your interent go faster than your 65K rwindow u have. GEEZ!