r u going to be putting the camera indoors or outdoors? that makes a difference in price and size, and also, at the very minimum, ull need to run power wires. also, since u live in a townhouse, make sure ur allowed to install the camera outside since most townhouse strata rules dont allow u to do shit to the exterior of the houses.
if its inside, then look into something called ip cams, theres many different brands out there, and most of them r wireless, high resolution and offers remote view via internet browsers and iphone app.
i have 2 of these in white, they were around $1200HKD each
iPUX