You don't disable the router firewall, it will take care of the inbound firewall actions to the point that PC Tools firewall would have nothing to do but possibly catch something that may get past the router firewall.
The PC Tools firewall would take care of the outbound connections and the router would be none the wiser that something had been blocked before it gets to the router.
The two firewalls are operating on different levels one the router, outside your system and PC Tools firewall on, within your system and never the twain shall meet. So you shouldn't have any issue just install the software firewall.