If perceptionsystem.com is your site, you have a PageRank 4 right now and 39 backlinks showing in Google who is "fussy" about what they consider. Yahoo is less fussy and shows 4,485 backlinks to your site.
You site also offers SEO services and Link Building, so I'm surprised you are coming to this site asking for advice? Do you really not know abut SEO and link building or are you just trying to get people to visit your site?.
Since your site is for a non-profit it is not appropriate that we provide much support for you, but this topic is relevent to our members and bears more discussion and analysis.
The first thing I have to ask you is while you are seeing the number of links change, what is happening to the traffic numbers? PageRank may or may not reflect traffic numbers and often it does not. I have launched sites on new domains that started getting nice traffic within a few week, but still had a PageRank 0 (PR0).
In my opinion, being worried about PageRank is about being worried about thunder. It's the lightning that you should be worried about. If your site traffic decreaes there is a reason for it and that may be on-site or off-site. And changes that are made to a site can effect the traffic so that would be the first place to start looking. What changed? If nothing on the site changed, then you have to look a your web stats and see what is different about the traffic. Is Google sending you less traffic? A partner site? Are you still getting traffic from Yahoo? Yes, there could be many reasons.
So, while likes CAN be beneficial AND send you traffic as well, most SEO consultants will tell you that the best and most enduring form of traffic will come from having a lot of good, optimized, text content on your site.
And if you want more links, well where did you get the ones you have now...? :-)