Lane Bryant is a very good store for plus size clothing. They also have great prices on good quality clothing. They are in most towns.
Size 18 onwards can normally be considered plus size womens clothing,
Eddie Bauer, JC Penney, and Just My Size make clothing for tall women. Avenue has a whole line of clothing dedicated to big and tall women. Big Lion has plus size clothing and clothing for the big and tall.
Delta Burke has a line of plus sized clothing. Chadwicks also offers large womens clothing. You can request one of their free catalogs to be sent to your home. Many popular designers have plus size clothing lines. Calvin Klein, Ralph Lauren, Michael Kors, and Tommy Hilfiger all have stylish clothes for any woman's needs.
There are several options availble for you. I highly suggest the following: www.lanebryant.com/, www.alight.com/, and www.avenue.com/womens/clothing/plus-size-clothing-sale .
You should look for Plus Size Clothing stores. Avenue Plus size clothing on Brodie Lane And Southpark Meadows Shopping Center are two of such shops. I would suggest looking at www.filthyrichfashions.com. And beleive it or not you can find a good selection of big and tall womens clothing at Walmart.
JC Penny and Sears both offer plus sized clothing for women. Prices vary based on the type of clothing.
Macy's does offer a relatively large selection of plus sized women's clothing. They carry clothing lines like J Jill that offer very stylish clothes for the plus sized.
Queen size in women's clothing is what is commonly referred to as plus size clothing. This ranges from 2X to 8X and are reserved for women with big bodies.
You need to watch your budget and find great tops for your mom. You need look no further than Trendy Plus Size Clothing: http://www.avenue.com/womens/clothing/trendy-plus-size-clothing
Talbot's and Torrid are a couple of the biggest online retailers for plus-size female fashions. Torrid is especially appealing to younger women. Lands End and Lane Bryant are a couple other options.
Plus size label is usually marked with a W after the number. The sizes range from 14W to 32W
From my experiences, I have never seen Jones New York clothing items in plus sizes. There is a possibility that a special Jones New York line that caters to plus size individuals does exist.