Getting a New Dog, Advice pls Options

I love dogs and have owned several guard dogs. Until years ago, one of my girlfriend introduced me to a toy dog breed and now I owned an imperial shih tzu for 2 years I loved dearly called Mouchi.

A few months back, I bought a Yorkie (yorkshire terrier) named Tasya which are very much terrier at heart. She was very active and naughty. Mouchi hates her. Tasya likes to charge Mouchi's ass like a bull for the fun of it, and at one time she was so naughtly excited chasing Mouchi's ass around the house, she fell down from the second story and to my dismay Tasya died. Mouchi seemed relieved though (IMG:style_emoticons/default/rolleyes.gif) and don't have to protect her ass from Tasya anymore.

I wanted to get another toy dog, especially a miniature schnauzer, a westie (west higland terrier) a pug or at the very least another shih tzu. It seemed Mouchi is not very sociable to other dogs and I'd like to have a dog who at least doesn't frustate her as Tasya did. What breed do you suggest I should get which may have compatible temperament as Mouchi's playmate?

Thanks for the replies. I do want a puppy than a mature dog though. Rarely people here will sell mature dogs except guard dogs for business premises. If they do sell mature dogs for pets, then I will question their motives and the dog's temperament. I am still confused. Mouchi definately does not want me to get a new puppy since she seemed to want to own me for herself (IMG:style_emoticons/default/13.gif) yet I missed Tasya terribly. She was terribly cute.

I'm not sure what to do. If I adopt new yorkie, then the possible new naughty pup may shorten Mouchi's life (if she's as shockingly naughty as Tasya) but then, I could pick a less active puppy from the pack (I did pick the most active and friendly one when I picked Tasya) Second option may be to get a shih tzu pup since the breed are much less active than a terrier, usually very well mannered, quite and aloof.

Undecided... (IMG:style_emoticons/default/sad.gif)