Internet 2g/3g network issue

My phone's preferred network type is only 1. 2g. 2. 2g/3g. And I chose 2 there is no other selection which says 3g only because the 2g/3g I chose only stays at 2g which is edge and it very slow so how do I get a menu to the 3g setting or how do I change it to 3g.