Repair OS X Snow Leopard without DVD and Single User Mode

First off, thanks to all those who have taken the time to post on this site. I've taken countless tips and wisdom regarding these machines from here, I can't express how much help it's been.

Now onto the issues I've been having. Long story short, it's still a long story; so I'll start out with the most prominent one that I'll need resolving before moving onto any others:

How would I be able to repair my hard drive disk (via the Disk Utility repair disk function) without a Snow Leopard OS X Install DVD, and without being able to boot into single user mode?

I mentioned I have been running into countless problems, but the most recent/dominant one is getting my disk back in health. I have successfully been able to repair permissions; however, when it comes to verifying the disk, it stops the process a few moments in and gives me this:

"
Verifying volume “Macintosh HD”
Performing live verification.
Checking Journaled HFS Plus volume.
Checking extents overflow file.
Checking catalog file.
Checking multi-linked files.
Checking catalog hierarchy.
Checking extended attributes file.
Checking volume bitmap.
Checking volume information.
Invalid volume file count
(It should be 825608 instead of 825610)
Invalid volume directory count
(It should be 174488 instead of 174486)
The volume Macintosh HD was found corrupt and needs to be repaired.
Error: This disk needs to be repaired. Start up your computer with another disk (such as your Mac OS X installation disc), and then use Disk Utility to repair this disk.
"

So, ok, not a big deal. All I have to do is make a quick backup of my important docs (I have a 320GB WD External US hard drive, no external power source needed) and boot from my install DVD as it says. Problem is, I don't have my install DVD! I have no idea where it went. The most reasonable possibility is it's buried somewhere I haven't already looked in my college stuff. I also may have packaged it with my old mac once I sold it on accident (which wouldn't make sense, I already had it bundled with the Leopard OS X disk it came with). Anyways, I don't have an OS X Install DVD. So I downloaded a full functional .dmg of one in which to throw on my external hard drive in hopes to boot from that (I made sure it was a bootable GUID partition). When I try to reboot from the external HD, it just sticks at the Apple Logo load up screen; I've let it sit for roughly 40 minutes to no avail. OK, so external hard drive won't work. I tried using AppleJack (let's you operate permissions and disk repair in single user mode) and rebooted into single user mode (Shift + S after Mac "Chime" on boot) but single user mode sticks too! It successfully displays the black screen, with the boot text and whatnot; then when it gets to the "loading drivers" segment, it freezes! I've let this sit for some length of time as well, no success.

Anyone able to wrap their head around it?! I adore Apple products, because they just WORK. Now, I'm a pretty positive guy who believes I'm just trying the wrong things; but Murphy's Law holds its ground! ESPECIALLY dealing with technology. I'm giving the benefit of the doubt here, and saying my problems are operator error bases, and not Mac based. I have much, much bigger things to tend to, so I'd be incredibly thankful for anyone who's able to shed some light on what may be happening here. I'd be happy to give you any more details upon request.

Oh, and Happy Valentine's Day to all you other single users out there, lol.

Matt