For the TV: You can buy PAL-to-NTSC converters, but they will run $300-to-$500 USD. You'll also need a power converter for the TV but not just a plug adapter; you will need a trasnformer type converter rated for the TV's wattage.

You will also need a transformer type converter for the rest of the audio/video gear. You need to add up the wattage for all of your gear plus TV and then buy one converter that will handle that total amount of watts. You are probably talking around $60 USD. Examples can be found doing a web search. Here is one site that comes up:
http://www.voltage-converter-transformers.com/step-up-transformer.html

If your gear is really high end and you want to get stabilized power, you might want a converter with voltage stabilizer. About $80. I'm not really sure that you need a stabilizer in Qatar, but for an extra $20, it might be worth the peace of mind. See http://www.voltage-converter-transformers.com/deluxe-voltage-stabilizer....

Note: I have never purchased from that store. They just have good examples of products.