For once I agree with OW. Let it expire for everyone. As for the poor, well, the bottom 40% of wage earners in the US don't pay any federal income tax as it now stands--and they'll continue to get the same sweet deal.
As for a national VAT: it would require a constitutional amendment, and good luck with that. But if it were so bound to the exclusive purpose of paying down the national debt to a specific % of GDP--and if Dems didn't turn an in-kind portion of the general fund into yet another state welfare program--I'll bet more than just a handful of righties would go for it.