Need help: Upgrading to Delphi 2 and WinNT Server

I'm developing a database application for a small company using a
MS-DOS/Lantastic 6.0 based network.

Current setup are:
Standalone server: Pentium 75Mhz 16Mb Ram (512Mb HD)
2 Workstations: 486 DX/33Mhz 4 Mb Ram (Diskless)
4 Workstations: 486 SX/25Mhz 4 Mb Ram (Diskless)

My current MS-Dos-application (with data) occupies about 40-50Mb harddisk
space on the server HD.

I've got Delphi 2 Developer, but im not sure what network upgrade to
recommend the company.

I've also heard rumors that Lantastic and Delphi doesn't work very well
together, so if the company installs Windows NT Server and Win95 on all
workstations, what is the minimum (recommended) configuration
(CPU/memory/HD) needed on the server/workstations?

Do I have to buy NT and/or Delphi 2 Client/Server to develop NT Network
apps on my computer?

I'm greatful for any help/hints here.

-> Robert