Oh thank doG you have changed your mind!! Well done you for persevering! I know it can be very scary when it seems like your dog is out of control, but with the right help, Im sure you can work through this.
You have had loads of good advice on here about finding a good behaviourist, and you also have us. So please stay in touch on here and give us more details if you can, of individual attacks, his age, how long he has been like this, if you have had him since a puppy, what roles you and your mum have with regards to his training etc, and we will be able to give you far more advice. (well, not me, but the more experienced cocker owners!)
There is a whole big family of people on here who will give you any amount of advice you can take, and so please make use of us!
Big hugs and lots of luck x