Budget for a years travel around South America - Advice wanted!?

Just wondered if anyone who has actually traveled South America for year could give me some advice on budget. A friend and myself are heading to South America next month and are hoping to see the travels out for a year if we can!...We have a budget of around $9,000 -$9,500 (after tickets have been payed for) and we were just wondering how far that would get us around South America..and indeed if we could see out the year

We are going to travel Colombia, --> Venezuela,--> (back into Colombia)--> Ecuador,--> Peru,--> Bolivia,--> Chile, --> Argentina,--> Uruguay,--> Paraguay --> Brazil

Not really interested (well yes we are but we wouldn't loose any sleep if we didn't go if you know what i mean) about visiting French Guiana, Guyana or Suriname due to the fact that it seems expensive & we would be hassle to get visas etc (We are 2 British travelers by the way)

I know according to the LP the so called cheaper countries are Colombia, Ecuador, Peru, Bolivia & Argentina so our plan is to spend more time in these cheaper countries...

I know it all depends on your spending habits so im not really looking for any responses that say 'depends if you like to got out drinking' or 'depends if you like going on tours' etc ...Just would be good if someone could give their opinion of a rough ball park figure from someone who has experience and has already been there and done it.

We are two 27 / 29 year old fella's so we will obviously be spending on going out and sampling the nightlife, however at the same time we will not be going crazy, and will hopefully keeping a good balance to hopefully prolong the finances for the trip

Thanks to all who reply in advance, as this really will be invaluable advice & info for us!

Thanks again!