[support] Using different themes for normal users and admin

I have had a customised theme made which relies basically on 3-4 tabs at the top of the page.

The problem is, I don't know how to organise things on the admin side. I would like to use a standard theme like Garland for the admin side but wouldn't there still be a problem of where the admin menu links go?

The new customised theme will not have a left side menu....only the tabs I mentioned. Is it therefore possible to use Garland for admins WITH a side menu or does a menu have to be in the same place for all themes? What do other people do to have different themes showing to their members and themselves? I know you can alter the admin theme - it's just this issue of menus that has foxed me.

Neil