Captain EFIS is right. On the other hand I have known of pilots who have bought the 737 type rating in order to increase their chances of employment, being rubbished by GA employers who are jealous of the type rating and missing out on GA jobs as a form of spiteful reaction. It is a lot of money to spend just in hope, but there is no doubt that some pilots who took the financial risk, managed to score a 737 job, albeit months or even a couple of years later. Job opportunities in Virgin depend largely on the "mates" system - that is you have to have friends in high places to vouch for you.
If you have the spare cash it might be worth looking further afield such as SE Asia and decide whether perhaps an A320 rating might provide a better chance of getting a jet job. Austra;ia is basically stuffed as far as big jet first officer jobs are concerned and that will never change. Too many pilots as always for too few slots. Asia is booming with jet jobs although you may great difficulty in cracking the racial barrier.
Naturally Asians prefer to hire their own countrymen and who can blame them for that? Happens in Australia, too. You need to study the form and see which jet type will offer the better opportunities in the long term - Airbus or Boeing. Either way the financial burden is crippling and be prepared for disappointment. On the other hand you could crack the Asian market at the right time... But it is no good applying from Australia - you have to pack a bag and get going to find a job.