bind running on private ip address

[Alaa Alamood]

Hi

I have a static ip address which used by the router and, there is NAT 
system on there router

I register my IP to have a domain name in one of the companies that 
registrating a domains names

my domain name running on internal "private ip address" and the router 
configured to give this ip address access for domain

my bind server running on Redhat linux 7.2 with bind version 9.1.3, and 
when I run the following command

nslookup   www.yahoo.com

I get the answer with no problem, internal it working just fine,

my problem is

when from out side my network, I run the following command

nslookup MY_PUBLIC_IP_ADDRESS

I get not the same name of my domain, I get a name which registed in my 
ISP domain server,

also when I make nslookup as the following

nslookup -   MY_PUBLIC_IP_ADDRESS

*** Can't find server name for address MY_PUBLIC_IP_ADDRESS: No response 
from server
*** Default servers are not available

how can I make that when I make nslookup to my server I can get the host 
registered in that

I know it very long discrption, but this best to give a complete picture 
a bout what's going on


thanks in advance
Alaa