Yard sale to raise money for a friends cat, Should I?

My friends cat has lost 7 lbs, before she took it to a vet, she needs to do a huge amount of lab test and several X-RAYS. he absolutely does not have the money, I Said "Dina I have had my garage full of stuff for 2 years, since I have not used it I guess I truly do not need it, I will have a yard sale for you to raise as much money for you as I can". I also told her I wanted several signs make with the cats picture on it and we would say Cutie Pie needs Tests YARD SALE. have done this in the past and raised $750.00 one weekend, I had people actually simply giving donations once the saw the guinea pig and knew she indeed needed to have surgery.Diana manages an apartment house for seniors and today a couple of them offered to give $10.00, now she is all upset and said I can not advertise the yard sale, although she does understand it is a very important marketing tool.I had also told her today I am also kicking in some of my Gem stone collection, I was planing on taking some very collectible stones.(they are gonna be a steal for the buyers)

At this point I am so upset with her false pride I just want to walk away, however, the sick cat is bothering me.I was thinking I should tell her to suck it up and put a notice in the looby that I was doing the Yard Sale for Cutie Pie and if they wanted to do any thing they are welcome to donate an item to the yard sale. This way they are not out any money, I can hopefully raise close to $700.00, the cat can have all the tests it needs, and all should be well, Help here what should I do? Walk away? Make the donation suggestion? I am not willing to give my things away if we can not properly push it, it would be the difference between $150.00 to $700.00 I am open to any suggestions.