Right now I'm playing a little bit with this bot

Quite nice piece of soft.
Already modified it slightly to play with only "offset" of account money (to left certain amount of BTC untouched, still all fiat amount to buy BTC).
For the bug You are mentioning (strange prices) - should be easy to just eliminate/average peaks in price - have to check - as it is already working on my Gox account

Oh - just saw it selling - "BTC offset" seems to work.
If anyone interested - I can put the source on github when It's more tested/stable