Sorry I didn't get to try the setup at home last night, I was out pretty late....
But from your previous post of your config, it looked like you weren't NATing your inside IP's to the one DHCP address you get from your ISP. This is just what I have come up with this morning....
cable-modem---E0/2501/S0...........S1/2501/E0-------------PC
(192.168.1.0/24) (10.1.1.0/24)
For R1(connected to cable modem):
int e0:
mac ......(whatever the MAC you need to put)
ip address dhcp
ip nat outside
int s0:
ip address 192.168.1.1 255.255.255.0
(whatever WAN connection setup you want to make)
ip nat inside source list 1 int e0 overload
access-list 1 10.1.1.0 255.255.255.0
ip classless
ip route 10.1.1.0 255.255.255.0 192.168.1.1(S0)
ip route 0.0.0.0 0.0.0.0 24.210.112.1(E0)
then your other router, the one the PC is connected to needs just a basic setup with the WAN connection on S1 and subnet 10.1.1.0 255.255.255.0 on interface E0.
Try that, and see if it works, if not then post the configs of both routers. Hope this helps.
Burke