New Photos of Old Art

I'm getting 12 paintings and drawings ready to sell on Aug. 7, 5-8 p.m. at the Old Colorado City History Center, and it's been keeping me busy every day for the past two weeks. Only the 2 oils have escaped being taken out of their frames. I've taken each picture outdoors on our western patio in the bright southern sun and photographed it with my Minolta DiMage S414. I photoshop each picture in Corel 9, and am currently printing sets of 12 on my Canon Pixma pi4200 photo printer. Most of the new photos I've already posted among the 12 following pictures, but here are the two I finally just got done.
Sacred Heart in the Summer, 77, acrylic 18" x 24" matted



This is a startling improvement over the past photo I've posted (which I've left for comparison's sake in the June 24th post, to my embarrassment).

Sacred Heart in the Winter, 76, acrylic 18" x 24" matted



This is my favorite picture, and although I once sold cards of both of these paintings, I've never had the paintings up for sale before. I guess I just thought I'd keep them on my wall forever.
One big thing I've learned from this blog is how important it is to have good photos to post, especially of art. Now because my printer is so good I'm getting carried away making prints of all 12 pictures, which I'm signing in pencil and putting in clear plastic envelopes which I got from clearenvelopesonline.com. Each print, on 45# Canon matte photo paper, is ready for an 8" x 10" frame.
The thing about printing on a home printer is that the ink is not archival, and no matter how good the paper is the pictures may not seem so sharp after a few years or so. And besides, toner is darned expensive. I just like the control I have, but I'm too cheap to buy a printer that uses better ink.
So I have a question, please:
Should I instead pay to have these painting photos printed for me (from the UPS Store for example), or is home printing ok on a good printer?