Since you're free to add up to 49 cards in the deck before you need more agenda points, I'd add in some low cost "End The Run" ice. That way you can put it down in the first turn or two and stop a runner from accessing something important. Archer is more mid-game (and consumes a scored Agenda) and Heimdall is late-game. Rototurret is also more mid-game after they get out programs, but spring it like a trap when you know they can't break the subroutine.
If you're limited to a single core set then I'm sorry to tell you that a lot of the cards you've chosen only come as dublets..
Melange, Archived Memories, Heimdal, Viktor, Rototurret, Chum and Archer - if I read the list correctly (hard to remember so had to look it up ^^ FFG made a card list, easily google-able if you want it).
So you'll need to find at least 7 more cards to put in and as SynnerG mentioned it's probably a good idea to go all the way to 49 to dilute your agendas even more.
End the Run ice such as Wall of Static would be a good place to start.
Very helpful. Thank you. Going to make some revisions. :)
Are you sure you want to delete this decklist?