Re: New server suggestions
As an ex-DBA, there are about 50 billion questions here.... okay not that much, but it's not as simple as you think.
First, adding a second server at your location may help, but your database replication is going to cause the same issue you're running into now. If you mirror the databases, both servers have to acknowledge the transaction before the transaction is committed.. so if there's "lag" as you say, adding a server at your location and mirroring data will only make that worse. Plus, what happens when the connection drops and both location are inserting/deleting records? So the program itself needs to operate autonomously from the main DB and allow for transactions to be reconciled following an outage. SQL Server has all kinds of cool stuff to do this, but simply adding a server isn't de way.
In line with Cortb's response, it would be worth maxing the connection out and testing your throughput from A to B. Try to clear up, improve, etc that connection. If it's slow, and you add a secondary server... it will just compound the problem.
Me: You'd think as the dominant species we wouldn't be so effing stupid.
J: We're just intelligent enough to be completely effing stupid.