Pasta is the LAST thing you want to eat! If you're going to eat carbs, go for the healthy (non-starchy) ones -- veggies (lettuce is usually inexpensive) especially. As far as protein, when I'm having money problems (which is often), I eat a lot of eggs. Despite the bad rap eggs have gotten, my cholesterol has gone DOWN. Eggs have really been demonized. You can also buy meat from a wholesaler maybe (I don't know what you guys in Australia have access to). Buy whatever's on sale and stock up. I often get chicken for 39c a pound, or ground beef for $1.29 a pound. It's really hard when you're on a limited budget, but your health is more important. Eating refined carbs like bread and pasta is pretty much like poison to you right now, and probably to your husband.
You should also check out the Atkins website (again, I can't post the URL here), but do a search and it'll bring you right to the site. You don;t have to pay anything there and it has tons of wonderful recipes and meal plans that might give you some low-cost ideas.