Try this document here:
http://support.gateway.com/s/Manuals/Mobile/8512564.pdf
I have not tried it yet but looking at the document (Removing the old Keyboard topic), you can access the fan, remove it and replace it with a new one. Best way is to get the part number from the part itself and search the part in online stores for laptop parts.
On the second thought, since this is 6months old may be you can still return it and have it repaired or replaced under warranty.