Changing an extension & moving kitchen - questions

I have an old bungalow (approx 1000 sq ft) that already has an extension. The extension currently holds the kitchen and bathroom. There are patio doors leading out of the kitchen to the back yard.

I want more space in my house as a home office. As such, I was wondering if I can move my kitchen to another location so that I can use the extension space.

I've attached a rough sketch of my house layout, indicating where the existing kitchen is and where I would like it to be. The existing kitchen can be removed or left in place, but I would like the extension re-insulated or have the patio doors changed. If I do this, I would like to redo my floors before the new kitchen is installed too.

Some questions:

1. Do I need to involve an architect for this sort of project? Or should I speak with a general contractor/ home renovator?

2. What would a reasonable ballpark cost for something like this be?

3. Do the floors need to be done before putting in the new kitchen? I want to put laminate over old hardwood.