Digger, why don't you call the estate agents saying you're looking for somewhere to rent? Then you'll get an idea of the number of properties on the market.
There have been other threads in the past on buying in Tuam and alternatives to Tuam - they might help you further. (Some alternatives that come to mind include Abbeyknockmoy, Milltown, Dunmore, Corofin, Claregalway, or on the other side of Galway, Craughwell or Loughrea maybe?)