Vitamins

Not sure if this question goes here. Anyway, I was diagnosed 4/08. After my radiation and surgeries, my oncologist put me on vitamin D about a year ago. Now I want to take fish oil tablets. Not sure which way I want to go. I was in the drugstore today and there is either fish oil or krill oil. Both have the omega 3's. Now, the fish oil gel tablets are huge (about as big as a fish)and 1200 mg.  I did find one that I can take once a day. The krill gel tablets are 300 mgs. also once a day. Does anyone take either of these two? I had read that you should take 2000 mg. a day. If so how how would the krill with the 300 mg. taking one a day. Any input would be helpful.