I've had some experience in the area you are discussing. You see I went to Uni after leaving school, and pursued a Science Degree, as I really was not to sure what I wanted to do.
After completing this, I went to work for a electronics retailer, and it was here where I picked up my interest in IT.
I went looking for a job, without ANY luck! So I decided at the time, the best thing to do was to increase my qualifications so I could get into IT. I did a Masters in IT and then again went looking for work. No luck! The qualification was not specific enough to persuade anyone to hire me.
So I started working for PC retailer and then went and increased my qualifications further. This time I did an A+ in Hardware and Software, my Microsoft Certified Professional course, A Help Desk Analysis Certification and my Novell Netware certifications.
One thing that REALLY helped me getting my job was the last course than ran. It was Job interview skills.
The main point I got from it (which I hadn't been doing) was to ring the prospective employer and find out about the job, and then tell them what you have been doing. I always got a job interview out of this.
After 2 weeks, I had 3 Job offers. I accepted one in a School, and after 9 months I became the IT Manager. I have never looked back. Its a great job, and it get even better throughout the holidays!!
So my advice? If you've been offered a job, take it. Experience counts for a lot more than the qualification.
If you can fit it in whilst doing your job, Increase your qualifications by doing a degree, so you can get better pay.
Then do the extra qualifications if you want to branch out.