my second is the same way.... very independent, and a royal pain in the butt as a result!!! she makes me crazy.... when she discovered she could use her spoon (thanks to her DAD - i was trying to avoid it for several more months!), she was probably around 13 months too and it was just as you described.... she didn't want to let me help her or do it for her and yeah, as a result most food went everywhere but the floor....
the way i see it, there are two choices here.... let her do it herself and she learns that she can throw a fit and be stubborn and get her own way.... OR you can simply tell her that mommy feeds her or she doesn't eat.... that way she learns that MOMMY is in charge, not her!
so i made something i KNEW she would want to eat, i had the spoon and tried to give her a bite, and she flat refused, tried to swat the spoon away, threw a fit.... so i took her food and put it in the middle of the table and said "mommy do it, or no eat eat." we went through this several times during the meal, and as long as she refused to let me feed her, she didn't eat. she finally relented and let me feed her (we were having mexican night) and when i was done, i let her eat a tortilla and pinto beans by herself. since then, she's let me feed her. i think she just had to KNOW that i meant what i said. she is two now and she doesn't have any problems feeding herself (no more than your average two year old), and when i need to, she lets me feed her without any problem.
as far as your daughter being a poor eater, do you mean that she is picky? my second was
really picky at first (like she'd
only eat mexican food), but i kept offering her things she didn't like over and over again and now she'll eat almost anything.