About NAT and Routing rules for VPN

the routea ip is

br-lan

       Link encap:Ethernet  HWaddr 78:8B:20:6F:76:E8
      inet addr:192.168.1.1  Bcast:192.168.1.31  Mask:255.255.255.224
      inet6 addr: fe80::7a8a:20ff:fe0b:76c8/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:133862 errors:0 dropped:0 overruns:0 frame:0
      TX packets:147730 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:16392734 (15.6 MiB)  TX bytes:105873339 (100.9 MiB)

pppoe-wan

      Link encap:Point-to-Point Protocol
      inet addr:1.1.1.1  P-t-P:1.1.1.2  Mask:255.255.255.255
      inet6 addr: fe80::fcc6:7fbe:6e1f:82c8/10 Scope:Link
      UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
      RX packets:139822 errors:0 dropped:0 overruns:0 frame:0
      TX packets:126301 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:3
      RX bytes:105131865 (100.2 MiB)  TX bytes:18051118 (17.2 MiB)

How to make a route make let 192.168.1.2 go out from 2.2.2.2?