Recommended TRI BARS:
I personally favour the Vision series of TRI BARS. My own set are these:
...though at ~$600 USD may be a little too steep for some. If so try out these beauties at ~ $130 USD:
Syntace aso make some awesome bars such as the C2 Clip:
At around about $200 (AUD) these are a great buy, light (despite their appearance) and durable.
Most of these TRI BARS come in set sizes with limited adjustments, so make sure you get the right set based upon your forearm length.
If you prefer to buy from a local shop, either Glen Parkers or Total Triathlon will no doubt order some in for you.
A good tip is to avoid the totally straight bars as many complain of sore wrists after use due to the strange angle they put your hand/wrist/forearm in - look great, yes, but functional, maybe not?
A 2nd tip is to wrap handlebar tape around the ends to make your grip more comfortable.
Bar-end gear shifters are an option of course but this will all add to your costs don't forget.
Hope that helps!
Cheers
Paul