There are, actually, three answers to this.
1. There is a novel by a Polish author, Malgorzata Musierowicz, called 'Noelka', which does sound as if it was a diminutive of 'Noelia' by Polish rules of making up names ;D. It's not, at least not in the novel, but well, close enough. And it's my favourite novel of hers, one I read more than a dozen times and end up loving more every time. I loved the series before that novel, but can't quite like the novels that followed; 'Noelka' is my favourite and the last one I enjoyed.
2. 'Noelia Gin' was my sort-of self-insert character in Star Wars verse, when I was quite active in that fandom (that's what G is for, ya know, it's not for Giles like some people think and it's not for Gordon ;P). The 'Gin' part was, I think, after I watched Entrapment with Sean Conner and Catherine Zeta Jones, and her name was Virginia - 'Gin'. I liked the sound of it, her thief character, and the alcohol connotations. It seemed right for a smuggler in the Star Wars verse.
3. My very first Mary Sue character ever was called 'Elia'. Being called No-Elia still amuses me greatly.
All of those stories are true, but I can't remember how I really decided to become 'Noelia' for LJ and mail account, and, well, to most of my friends, because they do use it in RL, too. So, maybe none of those stories is really true when it comes to choosing LJ handle, maybe it just happened.