Trey ... when we were getting thoses kind of attacks (major ones on 2 of my mainstream sites, probably like yours), our host told us they could fix everything ...
Everything they did lasted for less then a day .
We sent an email to like 100 different hosting compagnies and some of them wanted as much as $50 000 to get us safe.
Till we found
http://www.theplanet.com/ who offered us a great service and had the hardware they needed to block the attacks ;)