Subwoofer Suggestion

I have a very budget system consisting of a Dynaco ST-35 and a pair of Klipsch RF-3 speakers. I recently switched to the Dynaco from a solid state solution, and while I really enjoy the new sound much better, I do feel that the bass is a little weak. Not to mention that the Klipsch are not so good below 40Hz.

I would like to augment my system with a little subwoofer action. I do not want the sub to stand out like a sore thumb, but want it to blend as nicely as possible.

The system is not really for home cinema, but more for music listening. I listen to all types of music, including rock, techno, classical, and jazz.

Can anyone recommend a sub that will just give me that little bit extra in the low bass department. Something I can buy used on this site for a few hundred would be great.

i always recommend the hsu stf 1, which hsu is listing for $259 on their website-- a great value. if you want to go cheaper, energy and mirage make very musical little subs which you can easily find around $100-150 on ebay.
Post removed 
I have the Paradigm 12. ABout 1700USD. Don't know the range. They are excellent.
a used james emb-1000 would do wonders for your system.