common use of internet provited by huawei 220

I have a mobile modem huawei 220 with which i connect to internet. I also have a router(TL-WR543G) which i have already programmed and tested in windows.
What I want is through my ethernet card to pass internet access to all pc are connected to my router.
I use knetworkmanager to manage my gsm modem, and I have connected my ethernet card to WAN input of my router. I want to use static IP to my ethernet card and give ip to my router with dhcp(if this is possible).
I have tried to manipulate route tables but with no success.
Please if is possible give me a methode how to make this task, because is essencial to me to get rid of non UNIX like operating system(windows),just for not been able to configure corect my harware. ty!!