Setting Up WAN or MAN

Sir,
My office is having H. O. office and branch in the same city but they are at least 25 KMs away from each other.
I want that these both offices should connected by a network. Whether I go for MAN or WAN ?
Could you please list the hardware components required for this purpose. I have Netware 3.12 Server and Win98 workstions at both offices.
Will it require a seperate phone line.
Please give a detail explanation.
Thanks
Amar Kasurde