Q about installing the CUDA driver and toolkit

My notebook driver is 186.81 and under the components tab of system information in NVIDIA control panel the “NVCUDA.DLL” is labeled as “NVIDIA CUDA 2.2 driver”…

¿Do I need to (re) install the NVIDIA CUDA Driver found in the “download CUDA page”?
¿If so, does it have to be the 2.2 version or the 2.3 version?
¿What toolkit do I install? ¿The one in the 2.2 or the 2.3 version?