Pressure hose are socks that are tight, so they help the veins get the blood back up to the heart. You can order them special at a pharmacy, because they are not usually available on the rack at stores.
I don’t know whether drinking more water would help or hurt. Swelling is edema, which is water retention, and the real issue is to find out why this is happening. However, a lot of women have “idiopathic dependent edema” which means that the doctors don’t know what causes it. It helps somewhat to put your legs up when you have a chance to sit down at home, but many of us don’t have that sort of time! 
As far as cramps, that can be caused by low potassium, among other things, but it is dangerous to supplement potassium on your own, because either too little or too much can be fatal. Next time you go in to the doc, you might ask him how your potassium is doing. And remember that cramps can also just come along on their own, without anything definite to cause them.
Good luck!