Has your hair been naturally short, or have you kept it to a certain length by cutting it?
Shoulder length hair is an acceptable length for hair extensions. I would recommend you go no longer than 16Ē which would come down to about your bra strap at the back. ...More >
If you find a good consultant, she should be able to supply your with the mixture you want without making it look too odd. If you have a sensitive scalp, or your hair is quite fine, then I would recommend one of three techniques: Hook and Latch (no thread no glue) Micro ring track (using cold bond and micro rings) this is very light and very flat or the integrated weave technique (thin cornrow with weft of hair added)
All of the above techniques does not have any individual stress points to the hair and gives even distribution throughout. The integrated weave is particularly good for hot weather or if you have a hectic physical lifestyle such as the gym or swimming.
With regards to your face shape, it would be up to your technician and self to decide on styling your hair after the extensions have been added. Tyra Banks and Cheryl Cole use different types of extensions to produce a certain look. If you have not used hair extensions before or have experience in working with long hair, I suggest you break yourself in gently, when you get use to them you can then become a little more adventurous.
What you should expect to pay should be between £230 - £280 for 100% Remy treated hair.