Router help

i am trying to connect my computer to a router so i can share its internet connection to my ipod touch and i keep running into the same problem that is i need an internet modem because i have a usb powered modem that runs off my computer. the usb modem runs off cell phone internet. i live in the middle of nowhere so i can't get dsl/ cable and we will get satellite internet later on next year. so i am stuck with this. so could you give me some help with setting it up without an internet modem