This is a great opportunity for social [let's remove the word media, we're not buying ads here] and really from what you've explained all the more reason not to worry about website traffic.
As you said, the goal here is fund raising and events. With a website that means trying to collect and bring back as many people as possible which is difficult as the day to day value of the site is minimal. Even if you posted a message every day it's still a manual visit for just that one object.
On the other hand the majority of Canadians [going from your bio] are on social networks already -- facebook and then twitter specifically. Thus getting a campaign going there with full value means you don't have to try and pull people off of another site, remind them to visit, or spend any other time in getting them to you, so you can focus it on what you say resonating with them. And since the audience can reply back you get the network effect [if one person supports it makes others more likely to do so] as well as a true feedback loop [the organization needs to be committed to interacting, not just broadcasting].
Then there's the insane virality... As you'd expected, non profits or for profit "civic-do-goods" are insanely popular to share as people who become fans themselves really want to spread the word. As a society we advocate our causes and social makes it so easy to show [or guilt] friends into jumping onboard.
Thus doubling down and making social more of a focus than the website makes total sense for social.
As an example, Habitat for Humanity Los Angeles which I volunteer for has an extensive website and a facebook page that's updated frequently with build shots, event invites, and volunteer profiles. I use the website functionally to sign up for times and beyond that have just about no clue what's on it. Why would I care? On the other hand their facebook posts appear all over my news feed which I'm looking at 10+ times a day and without saying anything about it that reminds me to sign up [or in the case of a monetary contributor, send a check] plus in one click I can show support or tell my friends to join in. Sure they can cross link to articles / blog posts but getting traffic to those is the exception and since they already have visibility they're winning on every post.
They're far from perfect but as a concept example it's right on...
Share what's happening so fans feel involved. Create opportunities that motivate people to step up both as it relates to money and beyond it [i.e. volunteers for the next fundraiser] and highlight the heck out of the super contributors so people see the bar being set. Assuming they have the right events & programs to gather interest, people will share, using your setup pages that they now know about, and bringing more people in. Traffic goes up, interest goes up, and with a good mix of content to asks, money goes up... without having to create a massive network yourself.
Metrics should be the same as the website: rsvp's to events, inquiries about the organization, media requests and of course cash. There's no reason why you can't build a tab right there to take money, track the clicks that come directly and of course ask around when people get involved to see how many use or came from social mentions.
That's my very long winded way of saying: I'd run hard into social for this type of organization. And kudos to you for supporting them too.