I'm so happy you're looking at your omega 3 intake. I have a few books you might be interested in reading.
1) Plant Based Nutrition and Health by Stephen Walsh, PhD; this one is more up to date than Becoming Vegan and covers topics in a different way. It's difficult to find in the US but Vegan Outreach carries it. Excellent book for vegan health.
2) The Ultimate Omega-3 Diet by Evelyn Tribole, MS, RD; this was published in 2007 and gives great advice for omnis and vegans alike. It's not too difficult for those who are not nutritionally inclined and as the book above, there are summaries at the end of chapters.
3) The Queen of Fats; a few years old (before there was vegan EPA available) but it gives a fascinating look at how essental fatty acids were discovered. This one is more for the medical/nutritional/science geek, I admit - but written by a reporter so not too dry.
All three of the above books go into detail about how important the omega 6 to omega 3 ratio is, how vegans have the worst ratio of all and how to fix it. I've been vegan for 3 years and omega fatty acids have only been on my radar for the past 2 1/2. I think omega fatty acids are one of the most important nutritional topics we can be discussing, especially as vegans. I'm glad you are taking a supplement.
However, you may not be aware (as I was not until a short while ago) that a Swiss company is producing vegan DHA/EPA capsules. They beat out the other two companies that have been producing DHA only supplements for the past few years. The supplements don't cost much more than DHA only and are available at Pangea and another online vegan store (I don't remember which one). However, if you're interested, the company has a 3 for 2 special at this time. The website is www.water4.net