The GOP will be fine. Just look at how the Dems surged back after they "imploded" after the 2000 election.
If you watch the whole speech, Rush Limbaugh actually makes a lot of sense, with the exception of the whole "I want Obama to fail" point. I, personally, don't agree with the methods used by the Dems to fix the economy, but I hope they succeed. The country needs success, no matter from what "side" it's generated. If what the Democrats are attempting doesn't work, then the Repubs will be back in 2010.