If you read your own post, you will see that you did not indicate how long it has been since your "tourist visa" expired.
If your 90 day entry permit has expired, there is a 30 day grace period during which you can ask for a prorroga de permanencia (extension of stay) at the office of migraciones in Retiro. Last time I checked the fee was $2700 pesos if paid prior to expiration. A 50% penalty.will be added to that.
If it has been more than 30 days, you will not be able to get the extension and you'll just have to pay the fee when you leave (with one "overstay "recorded in the system), but if you go to migraciones and pay the appropriate fee, as far as I know, you will simply have asked for and received a prorroga.
If you actually had a tourist visa (issued by an Argentine Consulate in anther country) that has expired, I don't think you will be able to extend it.
Even though you don't speak Spanish, you will really impress the folks at migraciones if you (at least try to) ask for the prorroga de permanencia in Spanish.
Someone might tell you to overstay and pay the fees at the airport, but I don't recommend doing that.