I would suggest looking for weekly accommodation rather than the nightly or backpacker accommodation... that way you get a cheaper rate and while you are working you dont get disturbed with noisey people who are just there to party... it can be frustrating!
Hmmm, some weekly accommodation places in Sydney... okya, here are a few links to some:
http://www.eastendlodge.com.au This is in the City near Kings Cross:
http://www.bernlyprivatehotel.com.au This is also near Kings Cross:
Im not sure of others, but I know these places are quite nice and affordable.
Oh, almost forgot for employment, I found this site with has some helpful links for temp employment in Sydney that you may find handy:
http://www.australiantravelguide.com...employment.php
Hope you have a nice time in Sydney!
Brad.