Get new gaskets on your drytop if needed and then spray it down with some of THIS
Get some cheap polarfleece from ebay/Goodwill/Craigslist for a base layer. Try a vest under your drytop to keep your arms free to paddle.
For the bottoms I used neoprene socks (warm), topped with goretex waterproof socks (dry) and then wore NRS Blackrock drypants. You won't freakin drown in them like some will scare you into believing. I've swam my ass off in multiple Class IVs with no issues at all. They are dry and warm and resonable. It's all how you layer the tunnel w/the pants. Keep your eye out for a used pair. Why be wet if you can be dry for the same price?
Cover your head with a skull cap and some neoprene gloves/poagies