They will fix it or give you a new/used one. Just because you can't buy one in the store does not mean they don't have any, but if they don't they might give you a UD3 model or maybe upgrade you to DQ6 if they still have them.

It all depends on what they have or don't have, but I bet they will still have your same model. I would not recommend a G41 or P41, or G43/P43, those are lesser chipsets, cheaper boards.