buckworks - 3:05 pm on Aug 13, 2012 (gmt 0)
I understand that by broadening my search terms, I risk spending money on ads which may be less likely to turn into conversions
That's not a problem as long as you're paying proportionately less for those searches.
Create some ad groups for the new products that are dedicated to the narrow search terms that you expect to do well. Make sure the ads are well customized for those searches.
Then also create separate ad groups for the broader searches that you'd like to test. Monitor your keyword query reports frequently, to watch for words that should be blocked, and also to watch for keyword gems that deserve special treatment.
Also, learn about modified broad match if you don't use it already.