BRITISH CHIHUAHUA CLUB. Sec. Mrs C Towler. Tel No: 01322 351961
CHIHUAHUA CLUB OF SCOTLAND. Sec. Mr G Baxter Tel No 01383 724368
CHIHUAHUA CLUB OF WALES. Sec. Dr Curr. Tel No: 020 8743 4073
MIDLAND CHIHUAHUA CLUB. Sec. Mr D Smith. Tel No: 01902 831679
NORTHERN COUNTIES CHIHUAHUA CLUB. Sec. Mrs C A Barlow. Tel No: 01524 752621
SMOOTHCOAT CHIHUAHUA CLUB. Sec. Mrs Grant. Tel No: 0121 782 4273
ULSTER CHIHUAHUA CLUB. Sec. Mrs E Jenkins. Tel No: 01574 275139
WEST COUNTRY CHIHUAHUA CLUB. Sec. Mrs M Greening. Tel No: 01249 783522
Here are some numbers to call, the breed clubs are the best place to start the search, but I would warn you you may not be treated with much respect when you ask for a "teacup"....offically there is no such thing, either here or in the US from reputable breeders. The term is mostly derived from puppy farmers/mills who have simply found a new marketing term that gullible members of the public are happy to fall for in terms of paying above the odds for what is already a toy breed.
I would also advise that you get an English person to call for you - perhaps your husband? It's well known over here in dog circles that an American accent will add at least 10% to the price.
Also, be sure to ask about conditions such as PRA/Luxating Patella's and all those health problems Chi's are "prone" to. A good breeder will expect to be questioned rigorously.