Krazyanime55さん、
Hajimemashite! I'm Kat, and I'll be hosting the Newbie lessons with Naomi-sensei from now on.
To answer your question... I'm assuming you pronounce your name 'leh' in English? If so, your surname would just be 're' in Japanese, since Japanese has no 'l' sound: katakana レ. So your full name would be ガブリエル・レ, or GABURIERU RE. Hope that helps!