Hi:
First, let me say you are a real survivor and don't ever give up.
It sounds like you have been doing some things that are making you money. I think if you "tweak" what you are doing you could really increase your profits.
Brent has listed some very good ideas for generating store traffic so I will comment on some of the other things you are doing.
If you have already had a yard sale, consider doing another one in a few weeks. You can get away with having about one every 4-6 weeks. Maybe try a friends yard. My advice is not to buy anything for your sale, find motivated people that are looking to have someone clean out their homes, garages warehouses etc. and haul their stuff away to sell. All you have to do is put a flyer together to advertise this service and distribute at least 300-500 flyers in a older, nice neighborhood. You will get calls. Or try a low cost, small ad in the classified section.
If you are limited on funds and depending on the area you live in, consider placing an ad looking for things people do not want, and focus on motivated sellers only. This could bring you many opportunities and if you have expertise in antiques you could really find some good deals. Just advertise "Will buy, Things you don't want." Followed by a list of items you would like to work with.
Note: I just had a mini-sale in my yard and netted about $200. If you want BIG sale focus on making flyers, signs and posters to get traffic. Also, if you are having any summer events near you, think about tying your sale in to those events. Since there is natural traffic. You can have huge days with $500-1000 cash from stuff you can get for free.
Good Luck and God Bless,
John McTighe
Make Money Buying and Selling