You have to work with an architect for blue print and elevation. You can go with L shape or T shape elevation as well.

Here is some rough rendering as an idea

This is what I want for my garden. 5 stars for idea. Cheers.

We had L shaped house, then we converted it in T shape with additional family room 470 SqF.

Thank you everyone for the great suggestions!

Celery's mockup is fantastic. you're lucky you already have black framed windows. I'd remove all shutters.

also, you're going to get a lot more of a "modern farmhouse" feel if you paint the bricks white. (note: your bricks are beautiful as is, I personally wouldn't touch them. but painting would really get the look you're going for.)