IMO a 5 lb female is to small to breed and just cause you want one of his off-springs is no reason to breed, you breed because you love this breed and to better the breed, IMO
Please do a lot of research before you make up your mind to breed, it's not all about putting 2 dogs together and making puppies, there is a lot involved and it COULD be very costly or even deadly.
Please read this entire page, it sure made me open my eyes about breeding to, like you i thought I wanted to breed my Kloey, why? cause she was so darn cute and I wanted to have one of her babies! But that is the wrong answer. here is the site, please let me know what you think after you read the entire page of her letter.
http://www.debbiejensen.com/table.html