Hey TogsTeam,
You've got three options for making this happen.
1) You mentioned this already -- moving to Quickbooks Online. Running on the cloud is likely the easiest way to do it, assuming the db migration isn't too precarious depending on your circumstances
2) You can look into multi-tenancy. This is typically a better option if you have several QB databases (franchising is a good example) rather than just 2, but if migrating to QBO is too much of a pain, this is the way to go. You can read more about multi-tenancy on Method here.
3) This is probably the best option for you -- IF your Quickbooks company file is the same one, then MEthod has no problem. In other words, if both computers are communicating via a network (likely remotely, or to a seperate server system like Right Networks) then Method can run with it without any problem. The only pre-requisitie is that it's the exact same file, rather than two seperate files or instances of a database.
Let me know if you have any further questions. Multi-tenancy can be a bit of a tricky thing so if you'd like to move forward with that, I'd recommend speaking with your account rep or dialing into our support line first.
Naeem