I've posted this several times so it feels redundant but look into Ubiquiti wireless products.  You can set up a wireless link between your house and garage with two antennas.  Then put a router in your garage.  It takes some networking know how to set up but once it is done it is faster than a wired network.  I'm not a big fan of running cat5 or 6 between buildings due to grounding issues and the length usually gets plenty long.  www.ubnt.com.