Default [Q] Looking for new job...where to start?

Hi there.

I work for the NHS as a community nurse but found that this is no longer what i wanted. Ever since my real passion is tech & gadgets in particular PCs, tablets & smartphones. I like selling them and giving advice to people before they buy them. I'm currently a seller on Amazon and Ebay but i only have a few items in there and would be very impractical as a source of income for my monthly things. Besides me and my wife have many plans and living in London ain't cheap.

If i have a regular job in-stores or act as an online or telephone adviser that might be more better and more practical. I know its not totally what i have finished in college but at least its something of a passion and what i really want doing. Don't get me wrong. Visiting patients and talking to them and doing what you are supposed to do is nice. I work from 0830 till 1630pm. But i'm in my late 30's and i need to be somehwere where i am "relaxed" and comfy on what i do. And i fell "at home" with tech & gadgets.

I also have this idea of creating apps for Android (or iOS) but with a very stiff competition it has to be niche and caters to very specific demographics, etc.

Any advice on how or where to start please?