IS THIS FAKE ?? PLEASE HELP?PLEASE

HI I REALLY NEED YOUR HELP..
I RECENTLY HAD AN EMAIL OFF TERESA ARMSTRONG ABOUT A AU PAIR JOB IN NEW YORK. I have just sent this agency she provided me £600 for mine and my friends visa?

i just need to know have i made a mistake ??

here is the email

Hello,

I am Teresa Armstrong, from New York, United States of America. My motive of writing you is to request your service as a nanny for my two kids. I am contacting you on behalf of our entire family (my husband, our two children and I). Basic about us you would like to know. Our family can be describe as a place where unconditional love, peace and understanding reign. We don't judge a book by the cover or take gossip to determine who will be around. We always try to stay optimistic and find the best in anyone or any situation including the worst ones.
I work for Toysrus as a sales manager and my husband work as a civil engineer. I am 36years old. You might be wondering why we need your service. Due to the nature of my job, I'm not always around. I'll thereby need your service as a nanny for my children. We are sociable and fun to be with family, looking for an enthusiastic aupair who adores children to spend their days enjoying their company. I look forward to your response to know if you are interested.

Thanks
Teresa

PLEASE SOMEONE HELP

It is a scam! The writing tells me that the scammer is African, not American.

Please contact Western Union or Moneygram immediately and see if the money has been picked up. If it has not been picked up, you need to tell them to stop the transaction NOW and reverse it.

Unfortunately, if the scammer has picked up the money, you will not be able to get it back.

You will NEVER be asked to send money to an agency for your visa. No legitimate agency will EVER receive money via WU or moneygram. A real agency will have one of their representatives in your country meet with you for a face-to-face interview before you are ever offered a job.