Jim's wife here - You will be amazed at all the adaptive equipment there is out there - An occupational therapist gave us a catalog of tools and equipment and it was very helpful just to see all there is. I just found this site for OTs: http://www.activemotionhealth.com/servlet/StoreFront
Click on bathroom and there are many pages of types of risers and chairs. We use a Duralife (www.duralife-usa.com) chair on wheels with arms and footrest. We like that it, 1. rolls OVER the toilet 2. rolls into the shower 3. rolls over to the sink and 4. has a removeable pan for using as a bedside commode. It has held up very well.
Prior to that, we had an Invacare (model 1391AP) raised toilet seat with arms when Jim could still lift himself up somewhat. I suggest you find what you like online, and if you can't buy directly from the company, take a print-out to a medical supply and ask them to order it for you. Shopping is no longer limited to what your local stores have to offer. I'm a big fan of google for information.
Your dear wife is lucky to have you, I'm sure.
Diana