OP,
If you already had several broken spokes on that wheel, then per my previous post, it's time to upgrade to a stronger/wider rim, like the 32 H Velocity Chukker. Use 2.0/1.8/2.0 DT butted spokes. The wider contact patch between the ground and tire will result in a better handling bike. Be sure to seek out a good wheelsmith to build that wheel. Specify 12 mm hexagonal brass nipples for a higher spoke tension on that Chukker rim. Chuckker can easily handle an extra 50% increase in spoke tension as compared to a traditional double-wall boxed rim.
You could replace all the old spokes and re-use the old rim, but you'll still have to pay about $50 for labor, and there is no guarantee that the rim will hold up to the extra load.
http://www.velocityusa.com/default.asp?contentID=700
http://www.sapim.be/nipples/brass/hexagonal
http://www.dtswiss.com/Components/Ni...exagonal-brass