AC Unit Replacement

Recently I noticed the difference in temperature through out our house.  This is when I called out someone to check on the AC unit; the unit is 13 years old.  ARS advised me that my unit was leaking freon, has ice on it and the 2.5 ton is to small for the house.  He gave me a quote for replacement which was way out there.   I reached out to get a second opinion and a third opinion.  I am choosing to go with the third opinion/quote who sounds more real for the deal.  However, I am asking for help to cover the cost for the replacement.  I do have some funds but not all of the amount, any amount will help at this point.  Please help get me and my babies cool again.  Right now we have the unit running non-stop, which in turn runs the electric bill up.  During the day it is warmer than at night, I do have fans going as well.  Thanks in advance for any support given to The Crockett Clan!!!❤❤❤