I will be stopping over in Hong Kong for 5 hours is their a tour or can I leave the airport to have a quick sight see. Will I need a visa

You can go to Tung Chung to make a short visit there. If you just make a transfer, the visa is not needed.

It takes nearly an hour to get into the city centre so you really don't have enough time. Tung Chung is a good option, but you won't see much... I don't think you'll find a tour available for such a short time. Hiring a taxi is probably going to be your best, and fastest, option, but there may be a bus available. You can check the HK airport website.

HK is visa-free territory for most of the world passports (except few developing countries & China).

HK Airport is among world's best, but in your case best idea is to go out and check out amazing city.

Fastest way is Airport Express train (only ~25 minutes to city centre), round-trip ticket has discount.

Once you arrive to final stop (HK island), you have several options at the spot:
1) Get 'Rickshaw Tours' sightseeing open-top bus, buy the ticket and just hop on it.
2) OR take taxi to nearby 'Peak Tram' and take the tram to The Peak (no.1 HK attraction)
3) OR take Star Ferry to Kowloon (land) side of the city, check out Tsim Sha Tsui & promenade.
4) OR stay on HK island side (it's like NY Manhattan) check out it's streets, or beaches, etc...
P.S. if your flight arrives late, or you lose time on immigration - cancel No.2, it's time consuming.

5) If you don't want to go to city, then you can take taxi from airport to nearby Tung Chung cable-car (world's longest cable car line) and go up the mountain to see Big Buddha and temples, interesting.
P.S. carefully note how long time you spend on taxi and cable-car, to know how long to stay there...
* If it's weekend or China holiday - don't go there, you'll stuck in long lines with tourist crowds.