Hi
First of all nice ink.
If you are wanting to link the cross and the triquetra, I would suggest a chalice that is catching the blood from the cross and have the triquetra worked into the bottom of that.
The clouds or smoke effect would also work well as filler around the edges.
I have used this many times as examples but is great for religious tattoos that might give you some inspiration.
http://www.religioustattoos.net/Other_Tattoos/Chalice/index.php
Take Care
Matthew