I usually hear 1%, but I have had a site perform at the 3-5% for a few years straight, now it is more around that 1%
The site is getting a little over 3000 visitors per month, it's a very targeted audience. Is that good?
If its very targeted then you have a much higher capability to have a high conversion rate. Once the visitors are on your site, its completely up to you to sell them your product or service, so the amount of visitors is fairly independant of the actual conversion process. 3000 / month is about 100 / day, which by most standard is pretty low. Not bad, a good start but definitely room to grow. The conversion rate also depends on the product you are selling, and or what you would consider a conversion. I have had lead generating sites convert at 7 - 8 % but selling products always seems to be much lower. High dollar products convert even lower, because there is often a very long research process before someone will buy.