I would use a three-tier design.
The best answer is to rebuild the app as a web page, and put that web page/app server as close to the database server as you can. That way any problems can be dealt with a HTTP issues, not as database issues.
If that isn't possible, consider using VMWare or Citrix to host your client and your database. This does the same thing at somewhat higher cost, but requires little or no conversion effort... Zero development, and probably very small administration effort.
-PatP