Laptop internet outside of my home?

i have a Dell laptop with a Belkin wireless router. the internet works outside my house on the porch backyard front yard garage etc but as soon as i am out of visible sight of my home the internet stop working. i know it has a range, but when i went to Dunkin donuts that has wi fi internet, my internet still didnt work. i am going to college soon and i want to sit outside my dorm in the park and do work or even the library. so do i need to buy an adapter for it to work outside? does it matter which adapter or does it need to be belkin also? anyways what do i need 2 buy for my internet to work outside in general.?