First of all, you don't want to be going into sleep paralysis at all, as this is usually super terrifying and should usually only happen if you have a sleeping disorder of some kind.

Now, to your problem - this happens to me quite frequently, and quite frankly I haven't figured a way to "get out" of my dream body and into my dream. What I do is wake myself up and perform a DEILD. Basically you want to take yourself up, and as you wake up you lay still, keep your eyes closed at all times, and you'll fairly quickly get back into dreaming, and you will fall asleep while being aware. It's honestly super simple once you can remember to lay completely still and not open your eyes, and it works for me

EDIT: Oh, and for some weird reason, the not being able to move thing actually sometimes has to do with the position I go to sleep in - I don't know if that could affect you too, but give it a thought