It's a 7440 bulb.
Lamp Replacement Guide View All Bulbs
Look at the link above... and find a LED replacement?
I got all of my bulbs from these guys.
http://www.yelp.com/biz/jlc-automoti...t_by=date_desc
Give them a call and they'll get you all squared away. Keep in mind you'll need a resistor if you replace the turn signals with LED bulbs to prevent hyperflashing.