Hey Irish,
Besides the Beatle Bar in Jaco, you can often find pros at the Monkey Bar across the road. For late-night action, check out Pancho Villa, a quarter mile away from the Beatle Bar.
My suggestion: Read these forums, use the search engine to find information on specific topics, etc. You'll find a wealth of information here, and most of your basic questions will have been answered already. Do a little homework!
As far as recommendations for chicas are concerned, Your Mileage May Vary. YMMV means that just because someone else had a fabulous time with a given girl, there is no guarantee that you'll enjoy the same level of pleasure. Your BPF (Budget per F*ck) level will partly dictate where you hunt, as will your personal tastes for body type, age, skin color, attitude. Are you a "Love and Leave (LAL)" kind of guy, or are you seeking the GFE (Girlfriend Fantasy Experience)? Or, do you want to live out your fantasies with a howling, growling sex machine, the Pornstar Experience (PSE)? It's tough to make recommendations; there are literally hundreds of girls in this business in Costa Rica and each is as different from the next as you can imagine.
Here's hoping that you have a real ball in Costa Rica! after doing a bit more homework, don't hesitate to ask any questions you may be unable to answer; we're here to help!
Hope to see ya!
If your going to be in Jaco in the am on the 16th, let me know. I can always have "one for the road"!