how hard is the ac drier to replace? i need to replace it

You need a mechanic.

Leaking refrigerant into the atmosphere can be illegal depending on local laws and regulations. Not to mention that if you inhale refrigerant it can also be dangerous to your health. Upon opening the a/c lines moisture enters and if not evacuated and correct amount of "pull" is used on the system there can be premature failure in the a/c compressor which will be an expensive part to replace.