None of them.
Best option if you send it out to print would be Costco. First use Faststone
to crop to exact size and save the file. If you use Costco, crop to 8 x 12
and save the file, there is no such thing as 8-1/2 x 12 paper size, you need
to crop to a paper size available. Upload to Costco and make sure you select
poster size for highest resolution, but better, copy the file on a CD and
take it to Costco. If no Costco around you try Wal-Mart, Walgreen (they all
have the same professional printers but Costco seems to calibrate and
maintain their printers better). They all have the same software to
increase the resolution of an image.
To give you an idea, 300 pixels/inch is top notch for great prints but you
can get a very good print at 200 pixels/inch. If you have less than this the
Costco software will do the best it can and it is very good. So you can look
at the pixel dimensions of your file and get a good idea of how good the
print will be. If you want 8 x 12, the pixel dimensions should be, ideally,
8 x 300 = 2400 pixels and 12 x 300 = 3600 pixels.
I suggested Costco above but other on-line photo printers will do the same,
like Smugmug, etc.
If you print at home, I doubt that you can beat Costco (or other on-line
printers, unless you have a printer in the $400.00 and above range) and then
the software to use would be Qimage. This is by far the best software to use
when trying to print a large print from a low resolution image, but the
interface is a little bit different than the software you mentioned, so will
need to learn it.
You can try a demo here:
http://www.ddisoftware.com/qimage/
Maybe you are worrying too much.
Place your mouse pointer over the picture file name or thumbnail. A text box
will open and will give you the dimensions in pixels. Tell us these pixel
dimensions and we can give you a better idea about printing 8 x 12.
However,