The best option would be to wear something thicker under your current boots. Like other recommended, the 2mm socks. The problem with what you're looking at is all it will do is keep your foot dry. There is zero warmth or anything added, so it does nothing. Your blood still gets cold, you need to shield more from the coldwater. If you had a sock under that, then it would be dry, and a warm barrier. If you are going to stay wet, you need more insulation. If going dry, you also have to add something that will warm it up, latex is think, and the water is on the other side.
Stick your hand in a ziplock bag, and put it in cold water. Your hand is dry, but still cold
Put your hand in a glove, then ziplock and water, and it's now warm.
hope that helps. Yes, it might be time for a drysuit, if you are just trying to get thru the weekend, some neoprene socks will help, as well as what Trace recommended with hot water. You can add some more as needed inbetween dives if you have it in a thermos.