Not sure what the content of the site is but I would say if AV related sign up to
google adwords for 2 reasons
1 - it looks cleaner
2 - You will probably make more than alternatives as it will be specific advertising related to your content as oppose to "Congratulations you are millonth visitor to this site"
Google Adwords pay on a cost per click basis, so everytime someone clicks on an ad you will get paid
Other alternative is sign up to an advertising network, same idea as above but they will mainly be graphical ads, so they will work paying you around £0.30 - £0.50p for every 1000 impressions that the ads generate as well as some ads which will be on a cost per click basis.
UK wise 2 of the biggest networks that do this are
http://www.advertising.com and
http://www.vcmedia.co.uk (whose main publisher site is
http://www.valueclickmedia.com)
Both pay on time and give you lots of control on the ads you will display, and are both worldwide companies, one owned by AOL the other listed on the Nasdaq so not mickey mouse companies you cant trust
For every 1000 impressions on ads from a network for a 468x60 average click through rate is around 0.15% and for a skyscraper (120x600) is between 0.2% - 0.35%
For adwords as they are showing related content can be much much higher as the ads are related to your content. Without being intentionally vague it really can be anywhere from 2% - 10% +
A nice thing with Google is you can implement a Search box and if anyone searches and clicks on one of the paid ads you earn money
For the number of uniques you have best bet is to go for google and also sign
up to amazon. If it works with your site dont go crazy but maybe have a 468x60 or 728x90 at the top of your site and a 120/160 x 600 down the side
With Amazon they have lots of flexibilty with how you can serve offers so you can include them without looking like overkill. Amazon with pay you a % of any books/products that are sold from your site
With your number of uniques you will probably make £15-£40 a month. Most companies I have mentioned wont pay you until you have earned $100/£100. But they will roll any money earned into the next month
My 2 cents on a few different options, and I am giving the advice based on working in online advertising networks for a number of years
So you wont be buying the island just yet

but should get enough to pay for your hosting
Hope that helps