I have a wireless network and all the clients have public IP's.
I was wondering if I can use in the same time PPPoE and hot-spot (on same bridge interface) and manage all from user manager?

I need this to separate permanent clients from laptop users (who need access just few hours or days).

Yes. See my posts in

http://forum.mikrotik.com/viewtopic.php?f=2&t=45185

And make sure you enable both hotspot and ppp in radius, and in their respective authentication sections.