Ah! I wondered about this too when I added Tikka.
Female dogs I think have more problems as far as wanting attention all to themselves, they don't handle being intruded on when their relationship with you is strong. Esp. by other females.
I think your best bet would be trying a male, see if anyone has a yorkie or small dog they would let you baby sit for a weekend to see how your girl does. She may love it, she may not be too fond of the idea.
We had a male pom first, he is very independent and keeps to himself. When we added Tikka right away we realized how needy she is! Always whining, and crying, and wanting on my lap, wanting to play with me... etc. Also if I'm petting Pooter then she HAS to be up on my lap too, and will pretty much kick him off.
I wouldn't add a puppy either if you say your girl is very attatched to you, she may feel neglected with all the time you'll have to spend with the puppy. Rescue would be great if you can provide the care it may need
My dogs love to cuddle with eachother, so they share a kennel when need be, unless one is sick then depending on the sickness, I don't.
As far as food, I'm working on that issue too, so I can't say much haha