...from my experience, for what it's worth:
Iams is by no means the worst commercial food out there - not the best, but not the worst, since most variants have a real whole meat as their first ingredient. Some don't, though, so read your labels. Almost every other dog food brand in the grocery store has "ground yellow corn" as its first ingredient (that is, there's more of this ingredient than anything else in the bag), and some kind of meat by-product down the list in third or fourth place. Even those brands that proclaim they're made with "real beef" or what-have-you, have the meat lower down in the ingredients list, and often in the form of "meal" or "by-product," which isn't the same as a whole meat source.
If you do feed kibble (and I do feed some, for convenience and while travelling, not to mention that most of my dogs are quite a bit bigger than yours and eat more!), go with a higher-quality brand. You'll have to seek out specialty pet shops to find it (Complete PetMart is the one in my area), and even they won't have all types. I tend to order online - I especially like Pet Food Direct, which has pretty much everything:
http://www.petfooddirect.com/store/default.asp?AffiliateCode=PF012803%2C+PF012803&mscssid=53FEE6JGMG6Q9LRGK71FU3CX6S605E4FI personally like Organix, Wellness, and Paul Newman, and there are other good brands too. Always look at the ingredients list and pick something with a whole meat as the first ingredient. Careful of the ones with a 40+% protein content, though - that's too much, IMO, and can lead to kidney damage. That's really only for working sled dogs and such.
If you switch to a natural/premium brand, start with a small bag first to see what your dogs will like. Without all the artificial ingredients and flavoring agents, some dogs aren't so interested in the higher-quality foods at first. Kind-of like switching from Lucky Charms cereal to Raisin Bran!
If you switch partially or wholly to home-cooking, remember that any time you give raw meat, you have to supplement calcium. I use powdered eggshells (coffee grinder is perfect for this!) rather than bonemeal, to avoid the risk of mad cow disease. If you feed beef, buy slabs rather than ground beef and cut it up yourself; ground beef is made with meat removed from the skeleton by machine, which can include bits of spinal tissue (again, increased risk of mad cow). I tend to like to freeze meat and later thaw it before feeding, just to help kill any parasites that might be there, but I've never had a problem with this.
All grains and veggies need to be well-cooked to be easily digested. Individual dogs will react well to some grains and badly to others; one of mine, for instance, gets digestive upset from oatmeal, while another does just fine with it. Small pieces of fresh fruit (but no grapes!) and veggies are fine as treats; lots of dogs like a raw baby carrot, for instance, and mine love pieces of sweet potato, watermelon, etc.
Many raw diet advocates will tell you to feed bones, and I've talked to lots of people who haven't had any problems and swear by it. I'm wary of giving bones myself because I worry about chipped teeth, splinters, punctured intestines, etc. Knuckle bones rather than long bones are supposedly best, and I would personally stay away from poultry bones no matter what anyone says. You don't
have to give bones as long as you have an alternate source of calcium (see above).
Hope that helps a bit. There will be lots more detail and specific recipes in your book when it arrives.
It does sound like there's an obstruction going on with Sidney, from the symptoms. It's good that she ate and drank a bit, but you still need to find out why she's in pain. This doesn't sound at all like an epileptic episode. Good luck to her, and keep us informed!