Probably overkill but Mikrotek Wireless wire is a nice prepaired 60ghz solution that will do 1Gbps over a 100+ meters, at around $400 it may be out of budget. I've got one setup and it's excellent full gigabit through it, and being 60ghz doesn't conflict with the existing 2.4ghz or 5ghz networks.
The mesh network points don't even notice it's there.