sorry man, i never touched galaxy w before. but it is using android right?

may be i just write down the step, u try to follow up, ok?

Settings > Wireless & networks
Mobile networks > Access Point Names
"touch" menu to open the menu, the "touch" New APN
inside the new apn, key in:
Name: DiGi BB
APN: 3gdgnet
"touch" menu again, "touch" Save
After you saved it, tick the APN u just created.
then back to the mobile network setting, the "touch" to ON the "data enabled".
that should be work.