why i can't use all my sd card space on Apps?
It is because since older versions of android(i don't remember which exactly) its not possible to install or move apps to SD CARD without root.

All apps will be installed in internal memory by default however if you do root you can move them to your SD Card using apps(there are many) and at same time you will be able to delete useless pre-installed apps that is using your internal memory space.

Also i just noticed that u have 370MB of cache data, that data is near useless, since its just used to make things load faster but eventually it start to use too much space on your drive so you can safely delete the cache of all your apps, you can use apps for that...I use Cache Cleaner