If it's just repairing computers, Comptia A+ would be good enough.
Certification aside, you'll need to show that you've the technical expertise. Books can only you that much.
As a start, you can use old computers to experiment. Buy some second hand parts, follow the instructions on the book to assemble it. Then try installing an OS.
Next... remove one or two parts, then put them back. This will simulate an upgrade process. Or if you want, you can buy new parts and put them in.
These books can be borrowed from the libraries:
Comptia A+ books by Jean Andrew from Course Technology - http://course.cengage.com/certification/aplus.cfm
Sybex - http://www.sybex.com/WileyCDA/SybexTitl ... 48301.html
This book is practically a must for me.
PC Hardware Desk Reference by Stephen Bigelow.http://www.amazon.com/Bigelows-PC-Hardw ... 0072225254
One of the best computer books I've come across.
As for whether to get a computing degree, it would depend on what you really want.
In Singapore, we have vocational institutes. Quite a number of technicians graduated from there and could find a job without much issues.
If you're looking at software development, networking, etc, a computing degree would be preferable though. There are lots of computing degrees around, take a look at what they major in. E.g. Networking, Security, Programming, Engineering. Some are more specialized, especially networking and security. As you move higher, you will get to see the specialized fields in each major.
If you can't set your mind on something, a general degree would help. Working in the different departments should hopefully help you to decide on what you want to do.