My secretary swears by Ross Dress for Less. She even did some business on e-bay buying plus size from Ross and selling to overseas customers. She says that there are not many foreign countries with a good selection of plus size clothing. I was always amazed at the deals she would get that all were all under $20! She once did some shopping for one of the plus size women in our office for an out-of-town wedding trip. The end result was a suit for the wedding and seven other outfits for about $125.
BTW, each Ross has a different selection of clothes so go to as many as you can if you want to find the bargains.
As to your shoe question, you might want to try something like a mary jane style. If you go to Nordstrom's, they have a great shoe department.
TF