Betfair Betting Bot

I need a bot for betting on Betfair for Australian Horse Racing that works with the free API. I want it to scrape market prices from a website and compare these prices to the current Betfair Back and Lay markets. It has to calculate 3 prices for each horse which are used as triggers to place a lay bet & possible back bet. For example, The price of Horse A from the website is $10. The bot calculates a Primary Lay price of $11, a Secondary Lay price of $12 & a Back price of $15. These trigger prices are compared to the Betfair market & the bot places the bets. I'd like the bot to be able to automatically populate the runners list, but with an option for me to manually exclude horses as I see fit. The option to keep laying in play is essential. Experienced Betfair developers only please.