Root your phone then use Link2SD (available for free in the Play Store). It creates a secondary partition on your SD card so you can move all your applications there and the app links them to your phone, so the device sees them as if all the applications would actually be on your internal memory.
The program also functions as an App2SD app, so you can move your apps around. I would recommend to link all the apps you had moved to the SD card as well, because moving to SD card doesn't mean that everything is moved, all the settings and cache still reside on your device. Link2SD moves them as well. I would also recommend to set it to link all applications automatically so you don't have to move them manually, one by one. Sometimes this automatic process doesn't get done in the background, in this case you should do it manually.
