You need to set it up so that it uses your Linksys router as its gateway. However, it reads as if the Linksys router is an additional device on both networks and not the one router that all traffic goes through. If that's the case, then the computers on the remote side need to know to use the remote Linksys router as their gateway for talking to your phone (and whatever else you want to VPN). If I'm correct in my assumption that it's an additional router, that means that you'll have to set up a static route on every computer (that you want to be able to use the VPN) on the remote side. And, for that matter, on your side, too. This is likely to be a big pain.