Four hot dogs a day, and there are 10 in a pound package? Sounds like to much and too much fat. The hot dogs may be delicious, but are not the carefully formulated, complete and balanced diet that even the cheapest commercial chows provide. For a light eater, I would chose one of the concentrated, meat based dry dog foods, Pro Plan, Iams, Eukanuba, or a house brand. Put out half the recommended amount for a day at each feeding. Take up what isn't eaten in 15 minutes. Do not offer any more food or treats until the next scheduled feeding. Repeat. Adjust the amount to were all you offer is eaten. Check her ribs at least once a week. Compare them to this guide,
http://www.purina.com/dogs/nutrition.asp?article=292. This is not easy, but what is good for her to extend her life. With good care, small dogs are fine companions for a long time, always still too short. Grit your teeth and do it. I had a shepherd go 3 days without eating. She was fine, I was a wreck. Your vet will confirm what I say.