central air not working properly?

ok i have central air which usually freezes you to death.i have health problems which makes me have to have it very cool to breath,so i freeae all my company,lol.....anywayi noticed about 2 weeks ago the air was cool but not blowing as forcibably as usual,my neighbor came over and cleaned my unit which then was blowing great but several days later i noticed it was blowing with force just not cooling as well..i called my ex-husbands cousin who is licensed.well he said i did not need to be charged with freon i needed new coils,i had a restriction in mine.he kinda bypassed the retriction and it works but again not like it did.living in ga the humidity is killing me.has anyone ever had to replace coils before? i am looking at about 500 with him doing it .should i do this now or purchase another window unit till income taxes.i already had one put up and put it in my bedroom.it stays cool in here at night but during the day,,,whew....... let me know your opinion. thanks so much