You will have to open up your housing to install a projector which is called a Projector Retrofit.
Hit up Ebay.co.uk and type in 08 focus projector headlights or MK2 focus Projector headlight. I've seen about 8 different sets for around £219.95.
2013 Ford Focus BOOS[ST]ED
2010 Ford Focus "S"edan (11 Psi, GT28RS) - Sold
ROTM Nov '11 (2010 Focus S)