bedroom addition

I am looking to add a large bedroom addition (more than 300sq ft) to my home and have a rough idea for the layout. This bedroom addition will include an ensuite bathroom for added convenience. It is important to me to have a high-quality job done on this project, so I'm seeking an experienced professional who can guarantee a good result. We are adding on to an existing 1960 concrete block 2 bed 1 bath cabin on the lake. Current value approx 700k. We want the addition to be more modern with lots of windows marrying the modern design with the retro cabin.