Anytime you want to override normal routing behavior the solution is usually Policy Based Routing. Here are a couple good documents on PBR:
Basic PBR
http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_configuration_guide_chapter09186a00800ca590.html
PBR Multiple Tracking Options
http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a0080457bcc.html
In your case you may require another router on the other side of your IPS unless it can act as a router. If the IPS is layer 2 only you would have one 7206 interface and subnet connect to the other router with the IPS in-line, and a 2nd link direct between the 2 routers with another subnet. Packets inbound on the WAN would be policy routed with a next hop on the 2nd router forcing the traffic through the IPS. The 2nd router would normally route the packets back to the 7206 which would normally route to the intended site.
Please rate helpful posts.
Dave