Several people report they have built a simple press using bolts and
washers. I replaced mine using a combination of a simple hand press
I bought years ago, some plumbing parts, large washers and two trips
to the hardware store. Basically, you jury-rig up something to get
the job done (helpful to have a few boxes of junk parts -- the kind of
stuff you collect over the years).

On newer cars one end of the mount has a flared edge so you press it out
towards the flair and back in into the flair.

Also note the part has to be oriented correctly (it has a front facing
arrow for this, as I recall). Don't just press it in any random
orientation.

The other route is to cut out the existing one with a hack saw blade.
I believe this is what people do who then install the bushing sold
by IPD (which is not pressed in). (I've always wondered about shavings
dropping down into the engine area with this method.)

A search using "upper mount press" (down below, to the right) turned
up a few hits. Try:

http://www.brickboard.com/AWD/?id=561012