Well, if the original male and female were fighting, they were not a pair: they were a male and a female fish. A pair has a bond beyond being of the same species and breed with each other.
A 22*16*17 inch bowfront is a 20-22 gallon tank, not 45. Because of the bottom area, it is only suitable for a pair of rams or an individual (they are territorial). Personally, I prefer to see them in pairs and there are two ways to go about this:
- buy a male and a female which have already paired up
- buy a male and a female and hope that they pair up
If you want higher changes of success, the first is the better option. The second option is like taking a wild guess. You could try adding a female to the tank, and taking her back to the LFS is she doesn't, exchanging it for a new one, but that's not the most pleasant way to do things (for the females).
There really isn't a good way of getting a pair now that you have only one fish, to be honest.