Speedy Argentina Trip

So, I am in this little predicament because my visa expires September 16th, I am leaving the country for a wedding soon after, and I just got a contract or a job that will give me a visa.  All this and still, I have to get out of here before Tuesday or I could have a problem coming back.  I spent all morning in Extranjeria and was finally attended by the nicest and most helpful lady, but unfortunately she couldn't do anything about the fee for extending your visa.  I totally understand that they charge you to stay longer here, but it's cheaper for me to hop on over to Mendoza than pay the fee so I'm definitely doing that. 

 Sounds fine, but I really only have less than 48 hours to do so because my mom is coming to visit me (YAYYY) and she would not be thrilled to get to the airport only to find out I'm on a bus in Mendoza.  SOOOOOO, I think I have to use half of the money I saved to be able to treat my mom while she's here and hop on over to Mendoza.  Any other gringas who need to renew their visas wanna join me?  I think the buses don't leave at night during this time of year, but I'm going down to the bus station this afternoon to check out my possibilities.  Odds are, I'll be leaving bright and early tomorrow morning and coming back Sunday night.  

Luckily, this will be the only time I'll have to do this...