+1 for a lathe.
One of our cnc mills was donated by a local company that was upgrading. You would be wise to develop a community relationship... you might be surprised what would happen. I became a mentor after being approached to machine some parts for the team. I toured their shop and decided I'd give some of my time. A lot of shops push old equipment off into a corner thinking they may need it someday... maybe they could now use the space.
No for rotary broaching on your mill. I rotary broach hex shapes at work. You need a very rigid setup to get good results. It is great for blind hole broaching and production. For one off I use an arbor press. For key ways I always use a press. The key is a good arbor press with a ratchet and enough throat to accommodate the broach. A 1/2" hex broach is 11-7/8" long so ideally your throat needs to be that plus your material thickness. A quality set of keyway broaches should last a lifetime... some of mine are older than I am.
Here's some press details from duMont to guide your decision. The import arbor presses are a squeak too small in the throat, in my opinion. You can use them but you may have to "seat" the broach prior to putting it in the press.
http://dumont.com/bushings-shims-and...arbor-presses/
I have a Dake 1-1/2C (3 ton) with a 17-1/2" throat and it handles all nearly all my broaching except the really big stuff.
http://www.dakecorp.com/products-det...atchet%20Lever
For FRC you'll need a 1/2" hex broach and likely a few keyway broaches.
One of the issues we've encountered is the end of the year rush to spend left over dollars. That has definitely made for some poor decisions. What we've done lately is to develop a list of needs as we go so we have a need based buy list... and we can make a decision that isn't last minute. Otherwise you're buying tools you either don't need or don't have the skills to use.