Connecting iMac 21.5 to Viewsonic with HDMI

Morning all-

Been searching about this morning looking for an answer, but haven't found one yet unfortunately, so I thought I'd ask.

I'm currently running a 21.5" iMac that I picked up in October of '09. I also have a Viewsonic 21" monitor (nx2232w) that I have connected to the iMac at the moment through an HDMI to DVI cable out of the Viewsonic, and into a DVI to mini-DVI for the iMac.

The monitor is appearing and functioning in this setup, but I can't get a resolution of any decency. Most everything is out-of-range, or wildly odd, and I know I can do better somehow. I've been searching for Viewsonic drivers, trying out different combinations, and trolling the forums to no avail.

Is it the cable setup? Can I not use HDMI to mini-DVI in this way? Is it a driver issue? A firmware update? Or should I just go back to using the VGA port?

Any help would be appreciated! Thank you.

Sorry, should have included that.

I am up to date with all my system software, everything is downloaded and installed.

As for the Viewsonic resolution - the highest I can get it is 1024 x 768. The highest "number" that I see is 1920x540, which I know isn't right.

There are also TV options (480p, 720p, 1080i, 1080p) and a couple of those look halfway decent, but the text looks as if its been through a photoshop blur a few too many times.

Mirror Display is unchecked, as well. When check, both the screens jump into the 1024x768 style.