Debi this is a good starting point
http://www.ajcn.org/cgi/content/full/70/3/560S
Also use the search button above to search on flax and flaxseed. Flax seed has high omega three about 50% - it also is a good source of soluble and insoluble fibre - it also is argued to help block the ER recpetors - you will find it discussed here.
The omega three alpha-linolenic (C-18:3) some times spelt in other ways is turned by the body into DHA and EPA among other things.
Fish oil contains DHA and EPA and so save the body the trouble, or helps if the body is not making it properly.
I hope this helps. It is a huge subject with thousand of trials. From reading trials it is evident that there are very many unanswered questions, but most of the sign posts there are do point in more or less the same direction and for all the huge gaps there are a lot of sign posts - and that is balance your omega threes and sixes and eat some oil fish and or take fish oil.
Try reading the Zone Inflamation diet book - Cracking the Metabolic Code - Dr Gaynors prevention program.
Omega three and six are powerful factors in the body, particularly when complicated by treatment so you should talk to your advisors before making magor changes - print out bits that interest you and take them allong so they can see where you are coming from - some of this is relatively new research that is coming out and doctors are very busy people with a huge amout to keep up with.
Many people take both.
RB