Hi Ant.
Sorry, I don't know the company you contacted.
The RSMS visa is nothing to do with having family in Aus. If your sister is able to sponsor you then that is a different visa altogether.
I don't how how the family sponsorship visas work but there seems to be a selection of them here
http://www.immi.gov.au/skilled/general-ski...ons-outside.htmComing back to the RSMS which I do know about.
You have to find a company who will sponsor you in one of the recognised regional areas. Regional areas are defined by post code and a full list is in the link given by Catgirl.
It is a Permanent Resident visa. You are committed to the sponsoring company for 2 years meaning you cannot willingly leave their employment. If the company goes bust or you get made redundant then you are able to stay in Aus but just need to check with Immigration if you then have to stay in a regional area or not.
There is no point scoring for this visa. Normal cut off is 45 years of age but it does allow for exceptional circumstances. In your case you and the company would have to justify why the company needs to employ an over age person and one with no qualifications.
If it proves difficult finding a sponsor then you could try the more risky route of finding a company who would offer to sponsor on the 457 temporary visa. This is usually between 2-4 years of length. It comes with no rights that someone on a PR visa has. This should be viewed as a stepping stone to get you to Aus and later applying for a PR visa so needs some thought.
Good luck. :)