Looking for a bit of advice re qualifications.

I have a foundation degree in ICT , and have done various Open uni courses at the 3rd year level, in things that interest me and didn't need an exam in databases and Java etc.
As my background is webdesign and a bit of programming.
Then I went on to specialise in VLE's and creating online learning content for them. Before our team got made redundant.
I know how my own company which is just me and I am just managing to keep afloat.
So I work in schools a few days a week and work from home doing websites the rest. I have recently branched out into installing data cabling.

My plans were to move on to mainly web based stuff full time. However the schools work is a nice guaranteed income for the year where as web work is hit and miss.

As I work for myself I thought qualifications are no longer needed as, its me that employs me if that makes sense. My schools are happy with my work and I am learning loads of stuff all the time on the job. My main concern is that I am able to run a network once it is in place. However I have never installed a new one or migrated one. So in a few years time when we need to replace our server I wont know what to do.
My other concern is although I have my current schools which I got through word of mouth if I wanted to expand I have nothing really on paper to show future schools or businesses.
I have been concentrating on learning new web stuff as that's what I really enjoy, but think I need to start looking more at the network and technical stuff.

What would you recommend.
1 to make me more attractive to other busineeses and schools.
2 to help me with network installs and server migrations.