Two ways to look at this:
If you get the rents to $2,000 per month, you're looking at an 8% Cap rate - which isn't too bad for Southern California. Depending on the property and the location, you may want a higher (or be willing to settle for a lower) Cap than that. The question I'd be asking myself is how hard is going to be to fill a vacancy. If the church goes, will anyone else be interested in it?
The other thing you need to look at is the income. If you are going to resell the property to someone who will finance the property, the rents, less expenses, must support 120% of the debt service.
Start with your rent, then subtract out 10% for management, 10% for maintenance, 5% for reserve, taxes etc. After all that, the Net Operating Income should still exceed 120% of the mortgage. This may not matter to you but it will if you sell this to to someone who needs to finance the property. So to figure where the rents should be, just work backwards by adding in all the expenses and see where the 120% mark lies.
Finally, the commercial rental market is pretty soft right now. If you go raising rents, your tenants may be out before you know it since there's a lot of property available out there. Don't get too optimistic on raising the rents.