Link Between 2 Remote Site

We are having very Bad links,
The Telecom Company is forcing us to purchase its lines (Lease Lines, or Dialup)(Monopoly).

Q : There is a company in Saudi Arabia That uses SAP/R3 and they and that is connected to Europe via Lease Line -DDN(512KB)then to USA as there is the main Hub. That DDN Serves about 100 users on production lines & who needs to access SAP/R3 Process and Files (DATA & Drawings) and other Programs i.e. Oracle & Internet, but it takes a long time to open each page of file.so what do you suggest for an uplink between those 2 sites -24/7 online operation live , i.e.(Delectated DDN, Frame Relay, SAT “Not allowed”, X.25, ATM Switches & Fiber via Telecom Company) ?

Thnx .