I can not help you advice with prosthesis but I would very much reccomwnd you call the hospital and ask to be put in contact with the breast care nurse.
One visited me on the ward after my surgery last Friday and I have to say I have found her far more helpfull and informative than the surgeon both in terms of what to do and not to do to ensure speedy trouble free recovery.
She also had me go see her yesterday (1 week post discharge after I had my post-op consult with the surgeon) and again I found her incredibly helpfull as she also helped me clarify some forthcoming 'launch into Chemo' information (I am seeing an Oncologist on the 19th) and the info she gave me both about my diagnosis and most likely treatment options went way beyong the surgeon's info.
She also fitted me for a sports bra which turns out will be sent complimentary (free of charge) next week and was excellent in giving me more advice on how my breast was doing and looking as while I thought the size and shape I have now was it, turns out there are a fair gew weeks until all the swelling goes away so if fitted to the current sidlze it would be all wrong.
The same gorgeous lady did help me get more info on support for my hubby as I think he will need some to deal with what is coming (and by that I do mean 'me') since I want hom prepared for what I may need or how I may behave as (as selfish as this may sound) I intend to make the next few months all about me to give myself the best chance getting through Chemo with the least damage possible so hubby may have to suffer for a while but I am guessing his short term pain will be long term gain if I get through this so I intend to use all help that is available out there and preserve as much as possible of our finds seeing that financially this may be serious strain if I am unable to work.
I know your post was about prosthesis and I do hope you will forgive me for going off the topic but since you did mention you had not been put in touch with a breast care nurse I really trully believe meeting with one would help you enormously in being guided through this process.
They are really remarcable ladies and in addition to being just incredibly supportive they really know their stuff.