The radman is right

You must get it de gasssed by a pro, as said it will damage the envoirment and you could end up with a very large fine if found out!!

I run a air con regas service so i come across this problem all the time.
If the gas was to escape dont get in its way it will burn you. The gas is not toxic but again not a good idea to stand near by. It also contains a refridgerant oil which may contain UV dye this will not hurt the paintwork or anything else just make a mess.

I could helpout but i would need to meet you half way or you have will have a large callout bill.

The average price for a re gas service is around the £69 mark depending on the area

Hope this helps

Cheers
Paulcr