The canvas prints which professional photo studios (as well as some High Street photo processing shops) provide, at horrendous prices, are made using canvas which has been coated with a light-sensitive layer and then exposed in a darkroom. (i.e. they're 'proper' photographs, like the type you get from a film camera, rather than digital ones).
You can't match that quality using an inkjet printer. However you can get reasonably close to it. You need to print directly onto canvas, rather than using a transfer method.
The special type of canvas you require is made by Daler-Rowney, who manufacture art materials (such as oil paints). For that reason, you're far more likely to find it in a specialist art shop, rather than in a stationer's or computer shop. Alternatively, you can buy it online:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewIte m&item=250316966676&cguid=1586ea3911f0a0aad372 6542ffd2c022
Chris