Hello John,

STEP 1.  This is a very common for homes with room(s) obove a garage.  Replacing the window (s) in the bedroom  may not solve your entire problem if the glass package you select does not include a high performance  heat reflectant type glass.   Which ever manufacturer you decide, its best to pay the additional cost and upgrade to thier best performance glass.  If you have already invested in new windows then check your paperwork to see if there is a greater performance glass option you can upgrade with for that type window .   This is a simple process and can greatly reduce your Solar Heat Gain for minimal investment.

STEP 2.  Select a certified insulation professional in your area to provide you with a "critical point air seal".  Properly applied by a certified professional at upper and lower rim joists in this room aproximatly  1' in width by 2" in thickness. Air sealing the upper and lower rim is a minimal investment  and provides  a significant and noticable change in comfort with a quick ROI.  Consider this service for the entire home.

Warm regards

Colorado Home Exterior

I'd expect that you have a warranty longer than just 30 days. Probably at least 1 year, right? I'll base my answer on that premise.

In the first 30 days, you should look for things that are incomplete or not installed to the Standards Manual referenced in your contract. (My contract references the Residential Construction Quality Standards of the Wisconsin Builders Association.) If there were things promised in written or verbal contracts, change orders, etc that are not done.

Over the course of a full year, the lumber will fully dry out and the house will have gone through its seasonal shrinkage and expansion due to humidity & temperature changes. You should expect your contractor to repair screw pops and drywall seams one time in your warranty period. If you notice areas of trim that weren't puttied, expect them to touch it up then.

Any other things you can think of that you have questions about?

Make sure the room is well sealed. I don't know how old your house is, but there is a surprising amount of noise that can leak in around poor quality windows. If you need to replace the windows, find out about ones that are good for sound reduction, such as sometimes are retrofitted near airports. You could also add a storm window that specializes in sound reduction, again often used near airports. 

Here's a company that I know of. I've not installed this product, but I use some of their other products: http://www.monray.com/focus.htm#sound

Otherwise, if you install new siding on the house, you can evaluate whether you can add dense-packed cellulose in the wall cavities, or a thick layer of foam insulation under the siding. Brick masonry with a proper air space of about 1" could also help to absorb the sound and not pass it on through the wall.

Hope this helps.