I have similar interests in wanting to just gain better Spanish skills and perhaps apply them to working with Spanish speaking individuals! A year or two ago a memo came through our department about a program in Costa Rica that is for Psychology students and professionals where you can gain language skills while working with clinical populations. It's called the Costarican Professional Preparation Program (
www.crpreparationprogram.com). Last I checked though the website wasn't working so you might need to do some digging.
I also found this program in my search:
http://www.unibe.ac.cr/ccip/four_week.php
If you just want the language skills, there are plenty of programs that you can attend for as short or long as you'd like. I did one in Spain before I started grad school. I only spent 2 months there but was near fluent by the time I got home (after 10 years of Spanish ed too!). Perhaps a trip over the summer that wouldn't interefere too much with school work?