You may need to manually move the applications to the SD card. Some of the app data will still be stored internally, so there are still limits on how many apps, especially larger ones, you can install due to the rather small amount of internal storage.
I'm not sure which version of Android you phone has, but you should be able to go into your settings, then manually move apps to the SD card. Go into SETTINGS>STORAGE, then you click on Apps (probably second from top of list). Scroll to the left until you get to the "On SD Card" category, and click on the apps that do not have a box checked. You will have to do it for each app one at a time. From there you should be able to see the info about that app, and if it is possible to move it to the SD card there will be a "move to SD card" box on the lower left. You cannot move all apps, so on some of them this box will be greyed out.