DLink DWL-2100AP on Public IP Config

Hi Gurus,

I have DLink DWL-2100AP access point. We use iDirect VSAT for internet connectivity here in our environment. Our ISP has give us range of public IPs which we use here through our switch. We want to setup a WiFi connectivity here. What actually I want is to configure our DLink-2100AP Access Point for WiFi by assigning one of the public IP address(203.130.x.x) from our ISP. The AP should then assign IP addresses to the clients( ie. blackberries, iphones, laptops and other WiFi enabled devices) and connect to the internet. I had give in the LAN portion of the device the public IP address with the subnet mask and gateway information provided by my ISP. In the DHCP Server option i give these options:
IP Assigned from: 192.168.0.1
The Range of Pool(1-255): 20
SubMask: 255.255.255.0
Gateway: 203.130.x.x(Which is the public IP address of the AP which I had assigned to it previously in the LAN Setup)
DNS: ( I dont know what to put here)

by configuring in this manner the client are unable to get addresses from the AP hence no connectivity...
Please help me in this regard that what could be the correct configuration for my scenario...

Thanks in advance...