haha, I agree! If your Spanish is Basic or Intermediate, this should not get in the way, as any decent language teacher should know the difference between book and formal Spanish, and regionalisms or even porteñisms, as in local to Capital only. I think what you mean is you are worried about the variations of vocabulary from place to place. For example, in Colombia, you cancelar your bill at a restaurant and here te cobran.
Speaking of Colombia, if you want to conversational practice, there are sooo many well educated Colombians here in Capital studying graduate studies because of the high cost of education in their own country, it makes economic sense for them to get post Bachelor studies outside Colombia. You could always supplement your studies with a private tutor from somewhere else since they are often work part time jobs. What I find to be interesting about having friends from other countries from América Latina who are also immigrants here is they point out to me all the language encounters and communication snafus they have with Argentine Spanish, and it is quite funny and interesting! You could put ads seeking Colombian or non Argentine Spanish tutor on free posting sites like olx, or really in any public university graduate program bulletin board in the city.
Besides, sorry but it is proven that if you study a language after age 15, your accent will be a yanqui accent, para siempre. Join the club! : )