Networking problem

I've been trying to get a wifi signal from one side of my house (to where my wii is) to the other with no avail. I started off with a D-link WBR-2310. That almost got to where i needed it to be, but just off by about 10 or 20 feet. The wii could sometimes pickup signal, but never connect. I then bought the D-link 7dbi gain antenna and that didn't take the signal any farther. Yesterday i decided to try my luck with a Netgear WNR834B. It didn't increase my range any either.

My walls are lined with Firewall (thick metal sheets) and that is absorbing all of the signal after a certain point (the only place that i can get internet is in the very corner or my house).

I'm at a standstill right now. Can anyone help me?

P.S. my aim and yahoo im are speadskater69 if it would be easier to talk on there.