Backpacking in Ecuador - Where to go for wildlife

Planning to go to Ecuador for a month and a half and I'm mainly going for the wildlife. Since I'm on a $2,000 budget (is this considered a good budget?), the Galapagos is out of the question. Where would you recommend me going? I'd really like to stay in a cheap hostel close to the Amazon so I can just wake up and find some animals (tarantulas, snakes, etc.).