Newbie question re stepper size for small mill

I have a small floor modle mill (7 x 32 table). I am new to CNC but
have been reading everything I can find in an effort to educate
myself before asking a bunch of dumb questions. However, here goes. I
want to convert this mill to CNC on X, Y and Z. I think I have it
figured out how to do the mounting of the stepper motors but don't
quite know how powerful steppers I should be looking for and what
kind of controllers I will need. I have been looking on Ebay but
don't really know what to choose for steppers or controllers.
Naturally, I want to keep the cost down but don't want to do it over
by being too conservitive. After the conversion will I still be able
to use the mill in a manual configuration if I use dual shaft
steppers?

Also... is it feasable to convert the drive motor (1 1/2 hp) to DC in
order to get variable speed without shifting belts? I will soon have
a large 24 volt battery bank in an "off grid" home & shop to draw
power from. I will also have a backup 3 phase 10kw generator to run
my shop. If this is possible and reasonable then would the drive
motor be a stepper or simply a DC motor with some sort of speed
control?

Last question ... are the motors used on the old sattalite dishes to
move the dish a stepper type motor? If so, can they be used to drive
the X, Y, or Z axis on my mill?

Thanks in advance for your help

Mac McQuaid
Corvallis, Montana