From the rest of what I read about your job, a small arbor press will be
fine.

Hmm, Amazon.com has a half-ton arbor press for $27.00 without shipping & handling.


In order to use an arbor press, you need to fabricate a way to hold the
punch to the ram and the die to base so that they line up. Not too hard
for someone equiped with some metalworking tools, but I don't think the
original poster has much metal working equipment (if any).

A 1/2 ton is not very much push when it comes to punching.
According to roperwhitney.com,
http://roperwhitney.com/tech/chart1.cfm

A 1/2 ton will punch a 1/8 inch hole in 18 gage steel.
I doubt that is large enough to do what the original poster wants.