Currency abbrevition is wrong + How to...

1. Marketpress abbreviates Kenyan currency as ushs instead of Kshs. Note Ushs is Ugandan Shillings. How do I change this?

2. I want to limit options store owners can see. I just want store owners to access "products" and not be able to create pages, tamper with settings, etc. Seems my current installation allows users to be no different from admin