There are plenty of Apple Authorized service providers, you'll find that almost every Apple dealer is a service provider as well.
Here in Victoria we have at least 4. I checked with one; they will install RAM for $30 if you buy it from them, and for $45 if you come in with your own RAM.
If you want to install for yourself, two putty knives are better than one, they should be the thinnest, most flexible blades you can find, approx 2" wide, and it helps to grind the edge to a point.
Make sure you choose RAM from a seller that tests and guarantees compatibility with the Mini, and offers a lifetime warranty. Check out Canadian vendors, so you don't have customs clearing charges or hassles with over the border warranty returns.
Thanks
Trevor
CanadaRAM.com