Q: Sharing internet gives odd ip?

My tower has a really bad wirless car so I share internet via ethernet from my MacBook Pro which has a wonderful wireless connection. however, my tower is given an odd ip, 192.168.3.x while the rest of my house gets 192.168.2.x. This, although doesn't seem too bad, means I can't forward ports to it from my router as it doesn't allow me to enter the full ip to forward too, only the last part of the ip. I know it's because of my laptop that the tower gets the different if format because I unplugged the tower from my laptop top and enabled the wirless adapter and the comp got the ip, 192.168.2.60 assigned to it.

Is there a way to fix this, I would like to keep sharing internet as it is much faster than my towere's crap wifi card.