You will need a combination of a new longer shaft for each light and then spacers to raise the head of the light higher up from the bracket.
We will need to know how a long a shaft you think you need.
Our full list of available shaft lengths can be found at the bottom of this page:
http://www.unityusa.com/Full-Spotlight-Catalog_c_137.html
For reference a shorty uses a R length shaft which is 2 3/4" exposed shaft and 8 1/4" center to center.
For spacers we have 1/2" long, 1" long, 1 1/2" long and 1 15/16" long. Multiple spacers can be used together to increase height.