It seems from this excerpt from the USCIS website:
USCIS - R-1 Temporary Religious Workers
that you cannot file for another exemption. The first R1 is issued for 30 months and can be extended for another 30 months (which seems to be what happened in your case) but that's the maximum and your visa will become invalid after its current expiration.
If you are eligible to apply for a new R1 visa, it seems that this a visa which you can't apply for yourself but has to be applied for by the religious organization in the US to which you are affiliated.
The same linked USCIS website will give you all the information you need about applying for a Green Card