Expert Advisor for MT4 based on the half trend signals

Here is what i need the EA to be able to ( I think)

Using the half trend indicator

When the currency pair gets to a level that i like I want to be able to add/turn on the EA for that currency pair only -- even though I may have 10 other currency pairs open - i want it to work on the one i select --

once switched on I want to be able to select

1. Activate a buy at the next buy arrow or sell at the next sell arrow - I need to select the correct direction and option - i dont wanting it taking a sell on auto when i only want it to be a buy -- or vice-versa!!

There are a list of other things I would like it to do also but this is just to give the outline 

Not sure where the attachemnt is from so it would need checking over too 

cheers

Also please can somebody advise me how i find out or more about those that respond or contact them..?  thankyou