I think you would be in the $7,000 range for just the tummy and lipo to that area and maybe the flanks. The breasts at the same time would likely double that, because the surgery might go over 6 hours and you might need to stay overnight.
It appears as though you have lost a great deal of weight. I would not do this amount of surgery together and I would focus on your abdomen first. Make sure you use a licensed ambulatory surgery center in which case your costs will approach 7-8k to keep it safe.
You are a perfect candidate for an extended VS Circumferential Tummy Tuck in order to get rid of the saggy skin on your abdomen, sides and probably lower back and do some lipo to upper and lower back to help to improve the back rolls.
Breast lift is unsafe to do in combination with the very large surgery recommended (TT and lipo)
In Mexico your budget is reasonable for TT and lipo. Just be sure you chose a Board Certified Plastic and Reconstructive Surgeon.
Have a great journey.
Congratulations on your decision to have surgery on your abdomen. Typically, abdominoplasty and liposuction done by a board certified plastic surgeon in the United States will exceed the costs you mentioned when including anesthesia and facility fees. You should definitely consult with one or two board certified plastic surgeons who are experienced in these types of combined procedures as they are more complex in conjunction than done as isolated procedures. Best of luck!