I would not introduce a color that isn't already in the quilt (the yellow doesn't work imho). You can use ANY color or pattern that is already in the quilt, white, light-green, darker green, the blue from the logo.
Options:
Dark green inner border and a white outer border
Dark green inner border and shamrock outer border
Green inner border and navy outer border (same color blue as the logo)
Shamrock inner border and navy outer border (same color blue as the logo)