I think Mad Kiwi's advice might be the way to go. See if you can easily match quality of the image Blue Velvet provided. If you can do that with Aperture, then work with the images in Aperture initially.
It is designed to specifically work with multiples of images. It has 90% of the tools you are going to need, and they are fairly easy to learn. Within a few days of learning how to use the tools you should be able to get your photos close to "as good as they're going to get".
There will be room for improvement using the tools that are available in Photoshop, but the learning curve will steeper. You are going to be spending more and more time to get smaller improvements. Probably worth doing, imo, but it's a project that you can tackle over time as you learn new Photoshop techniques.
I don't use Aperture (but I do use another product that works basically the same way). If I were doing this I would make a copy of the image files, and put them into a folder for Aperture to use. I would also make another copy of the images, and put those on a CD as backup. If you are learning some new photo editing applications it is too easy to mistakenly start working on the backup image files instead of the ones you meant to work on. The CD, while not long term archival, at least ensures you have the original files protected.
As I understand it Aperture doesn't actually change the files as it works, it records the changes it makes. So it's always easy to "reset" anything you've done and start again. The changes you make are not committed to a file until you "export" (or whatever the term is that Aperture uses). This is the same as "Save As". Aperture then creates a new (second) file, with all of your changes.
An image that you are working on in Aperture can also be opened up in Photoshop (I understand from reading other posts) where you can use some more sophisticated tools, and then saved back into Aperture. It's supposed to be seamless.
Make sure you "Export" all the images before the Aperture trial is over. Or you may end up needing to buy Aperture. Which you may want to do in any case.
Good Luck.
...this is all imho, of course...