I'd recommend bringing extra clothes too. Have a set of dry clothes in your vehicles or get a waterproof bag to store on your Yak with dry clothes (in the event of flipping your vessel).
I purchase waders from Academy Sports and have had a pleasant experience with them. Although, I will be purchasing better ones in the future.
My winter setup: wear a Wool hat, get a face/neck gator, put on wool socks w/ toe warmers, purchase Under Armor thermal base layers, wear fishing clothes (Magellan fishing shirt/pants), have on old hoodie (like you want to be a UniBomber) and get some type of waterproof jacket/raincoat. Now, you might look like Ralphie's younger brother from the CHRISTMAS STORY movie heyheyheyhey. But, this keeps me warm for budget conscience fisherman. Throughout the day, as the weather warms up, I will downsize if necessary.