Nothing is irreparable... Taking the ISEB certification should help you greatly. In addition, as I mentioned earlier, consider applying for a related position such as project manager/coordinator. As a retail manager, I'm sure you had to organize things, manage projects, keep schedules, track to dos, improve the business operation, etc.
You should re-write your resume to showcase those types of skills. You resume should be a functional resume with your skills at the top: describe your skills outside the scope of a specific job. Remember - you probably have many skills that you have acquired from your education. For those which are relevant to Business/Systems Analysis - put them on top of your resume. For example: critical thinking, problem solving, logical design, pseudo code, data analysis, project management, issue management, etc. Of course - don't put anything on your resume if you are not ready to tell the recruiter/employer at least some details about that skill.
The resume could then include your education - there you might want to even list relevant courses which relate to business analysis: programming, analysis & design, business, marketing, accounting, etc.
Lastly, you can list your actual work experience. Don't forget to also include part time and internship type jobs if any.
- Adrian