hi there,
If you have applied for your RSMS (187 visa), you should have received a bridging visa A, so when your 457 visa expires, this will allow you to stay in Australia until your RSMS is granted. Im not sure wether this will give you the work rights that you are currently on with your 457 visa (could someone chirp in here?). It looks like they are taking between 6 and 9 months for 187 visas to be processed, and they are currently looking at visas lodged in early February, so should be within the next 4 months (this is just a guideline). I applied a couple of days after you and am expecting to get my visa by March at the latest(fingers crossed). If you cant get the work rights, I would be saving your $$$$ now and taking a couple of months holiday (around Australia, as the BVA will not allow you to re-enter Australia). Hope this helps, and good luck.