We think you should concentrate on creating a functional resume since you have only two brief job experiences to list. It will be most effective to present your skills and areas of knowledge first, then list your jobs by title and date. Do this well and you should be able to rouse an interviewer's curiosity enough to secure an interview. Slant your resume towards the retail sector by listing the skills required in that field first. If you need help in identifying and labeling your skills, check out "The Easy Resume Guide: A Transferable Skills Approach" (Hushion House, 1999) by Barbara J. Bowes. This book should help you determine the skills you can use to build a descriptive resume.
As for when to leave your job, we advise you to stay put for a while longer. There's no sense in putting the cart before the horse. Begin a job search after you've done some solid research into the retail sector, which may take some time. You'll need to talk with people currently working there to understand exactly what would be expected of you and how to best present yourself and your skills. Use your contacts to help identify possibilities and then secure a few interviews. Don't expect that you'll get the first job you apply for, but if you do, then consider yourself lucky.
Since it's fairly well accepted that IT jobs are constantly changing and tenure often is short, you shouldn't feel awkward about discussing your background at interviews. If you can demonstrate lengthy commitment to other activities such as volunteering or schooling, you may be able to counter balance the notion that you don't stick with things for long.