You’re right, we should just give up and wait ‘till 2016.
At the presidential level, yes. However, there is still much conservatives can do this election as far as activism and donations are concerned:
1 - Support conservative candidates down ballot who have a shot of winning local, county, state or federal office.
2 - At the presidential level, a vote for a third party or write-in candidate at least sends a message that you are not satisfied with choosing Romney vs. Obama.
3 - Educate other like-minded voters on the important of not choosing between “the lesser of two evils” but standing true to one’s principles.