I applaud you, girl!!!
Homecooking is very healthy for them!
There is a sticky at the top of this page with recipes. And yes, there are a lot of homecookers who will chime in here. I used to homecook - and I can't recall exactly how much it was per month, but I do know it was costing me more than raw (which seems odd, but it was). You do have to supplement - the calcium-phosphorus ratio must be balanced and some also add digestive enzymes, probiotics, vit E, C, lecithin, brewers yeast, Omegas - other stuff - it just depends on your dog too.
It could very well help her allergies, especially if they're food related. If they're seasonal - well - cooking could boost her immune system a bit and perhaps lessen the allergies. I will say that my dogs' teeth were their worst on homecooking vs. kibble or raw (best on raw). Poo should still be solid. And she'll probably LOVE the food!!
There is a book by Pitcairn that many recommend. I wasn't a big fan of it, but many like it - I think it really overwhelms the reader; plus, he recommends things that don't make physiological sense to me, so I just didn't like parts of it for those reasons.
GOOD LUCK!!