So after playing it through on the Xbox 360 and getting the trilogy on PC I was disappointed to find out that the DLC is still not included in a package. You have to buy each DLC separately. However with Origin.com's current deal offering 50% off everything, I tried it with Bioware points through Origin and it works! For instance Mass Effect 3 Citadel costs 1200 Bioware points which works out at £12.00 add ORIGIN50 code and those 1200 Bioware points become £6!
For some reason the ME1 DLC isn't available through Origin but you can buy all of Mass Effect 2's DLCs and Mass Effect 3's DLCs at the 50% off mark.