What variable speed motor to use?

Hello, I happened upon this group searching for info on
DRO's and machine tools, after reading a few messages I thought
I'd join. looks pretty civilized and informative.

I have recently purchased a Harbor freight 3 in 1 machine tool,
and I'm pretty happy with it, it's more than I expected of a low
priced asian import.
One problem with this one (it's the lathe mill drill, no power feed,
and metric feed screws)is the lack of speed choices for the lathe
spindle. it has only has 3 speeds, fast, fast, and faster.I'd like
some lower speeds and more speed choices ,and from looking at all the
options so far,
seems to me a variable speed DC motor would be the simplest way to
accomplish this.
So what DC motor/speed controller would be suitable for this
application?
the motor pushing it now is a 1/2 hp single phase AC motor.
I see many motors for sale on ebay and such, but I don't know
from "universal" "permanent magnet" "shaded pole" .... you get the
idea. I'm looking for a reasonably priced variable speed motor and
controller
capable of running this machine with a motor speed from 0 to 1500-
2000 rpm range... say about 1 hp. any info would be appreciated.
thanks.

Lee