It sounds like you're making progress but just not as fast as you would like. Keep doing what you're doing, but be careful with spun content. Make sure this content is readable. If it is not, then it will hurt your rank.
Another piece of advice...forget about PR. Right now, it means nothing. You are competing against well established authority sites (or at least authorities in your niche). Using their linking strategy is good, but not going to get you ahead any time soon.
Instead, you need to find more unique content that targeted traffic may be needing or searching for. Don't go after their traffic, create different traffic. Use long-tail keywords of terms that THEIR pages are ranking for.
Think of it like an auto race (or Nascar). The goal is to win, right? Well in our case, finishing in the top 10 is good (page 1 Google), but the top 3 even better. Just like racing, that's where the money is at. If you drive the same car with the same motor, but against more experienced drivers (12 year old domain vs. 3 year domain), how do you win? You win by tweaking and tuning your car (website) to perform differently on the same track (SERPs)!
It is a gamble and requires a lot of research and testing, but you can do it. I have done it with my Amazon niche sites. I have done it with my CB review sites. I have done this for Adsense MNS. Many aged domains have pages that rank well for a certain keyword, true, but you can outrank them for this same keyword if you follow certain steps. These websites often don't go back and change or tweak their content and it becomes somewhat outdated. If you are an authority in a niche, then it is easy to analyze your competitors' ranking pages and build stronger ones that have better optimization and stronger linking strategies. Then, you target a long tail keyword term and rank a page for it. Link this page to your other page and eventually your page will become more relevant to the SERPs.
It it a lot of work, but it is the quality that you focus on. The more unique, the better. The more long tail. the better. I use this technique to outrank Amazon and the manufacturer for a specific product that I am reviewing/promoting. My page is what I am ranking for, not my site. As a matter of fact, I really don't care about my homepage URL and the PR it has...that is not how I get traffic. Direct linking to my homepage URL still occurs but it is the content of my site that I care about and how each PAGE ranks - not the site as a whole.
PR will naturally happen over time but is not as important as people finding your individual pages through the search engines. Your individual pages promote a product or receive affiliate clicks so drive targeted traffic straight to those. That is how you will make money and where your focus should be.