Why would you run out of antifreeze? Do you have a leak or a BHG? I wouldn't worry about it if you don't. And if you do, you really shouldn't be driving long distances.
But to answer your question, you shouldn't mix the yellow and pink antifreezes. Its not going to cause any damage short term and OK for emergency, but you would need to flush it all out ASAP. Our systems hold over 8 liters of coolant. I would just add plain (distilled) water to your system if you need to add a couple of liters, then add proper Toyota antifreeze when you return from your trip to bring up the ratio to whatever you want it to be.. But being in Mexico (or California for that matter) in the summer, you will be fine if you dilute the antifreeze with water. If your current ratio is 50/50, and you somehow manage to loose half of your coolant, adding 4 liters (1 gallon) of water will dilute it to 25/75 ratio, which will be perfectly safe.
BTW, are you sure your coolant is pink and not red? Our trucks came with RED (long life) coolant from Toyota.
