Converting Stratum title to have owners corp

Hi,
I own a flat in Melbourne which has a stratum title issued 1966. I am selling it. The common land which includes the car space and backyard are apparently on a title held by a service company. So how do I find this service company?
I was also told by a solicitor that we could activate the owners corp and through a special resolution take out 99 year leases on our car spaces and backyards. But it seems more complicated than that as we are under stratum title. Do we have to convert to strata title before we can do anything and what does this involve in terms of time and costs? Anyone know? Thanks.