Josh,
I reckon with your numbers you won't be coming last so don't worry about that, there is no embrassment in competitions the people are encouraging as long as you respect the sport by playing by the rules.
I've seen people competing with poundages lifted ALOT less then yours, if you keep at it you will be competitive depending on how much hard work you put in it.
You can get the Singlet from a number of places, but the big names which make powerlifting gear are TITAN, INZER and METAL, which usually make powerlifting assistence gear but all sell Singlets. The bad thing though is most of these companies don't have an Australian Distributor so shipping cost an arm and a leg EXCEPT Titan
Titan Australia (Minh Nguyen) 0432-537-444
minh at titanaustralia dot com dot au
He can fix you up with a Singlet and Belt for a decent price.
With Deadlifting socks, you can get them from Titan for around $8-$10 but its pretty much just a any LONG pair of socks that has to cover all of your shins up to your knees.
Also is the Powerlifting Comp with Powerlifting Australia the 2009 South East Challenge on the 28th November 2009 at the Beenleigh Football Club? Because Powerlifting Australia doesn't hold RAW ONLY comps so it must be a different federation so usually different RULES as well for the lifts.
The comps for me is to lift in a competitive environment so i push myself to the limits with the encouragement of the crowd and fellow lifters. I usually use the comps as a Skill Evalution (1RM testing) to see if my training has paid off, so i always try to better my previous competitions result.
Good luck keep us update, if you have any other questions feel free to ask.