The board below shows the mixture of materials I used in the render above. This arrangement uses a charcoal duvet (use at the foot of the bed or reverse it seasonally), with a mist colored coverlet (like what you have now just slightly lighter but still won't show stains and whatnot from the kids). I used 3 charcoal euro shams to contrast the headboard and tie in the duvet at the foot of the bed followed by two king striped (with charcoal) shams and in front a pattern lumbar. The curtain panels also pull in a nice soft pattern with dark gray and neutral to pop off the lighter colored wall.

The second arrangement uses more solid colors with high texture. The quilted gray euro shams are against the headboard with 3 smaller sheepskin throw pillows (to soften the look) and one long body pillow with a pattern that embodies all the colors in the palette.
The duvet is heather gray and is very simple and clean with a white (or matching gray-euros) channel stitched quilt at the foot of the bed.

I think the mirrors are a perfect way to add light to the room and contrast the dark nightstands. I chose unique shaped mirrors that you can choose from for visual interest. Hang approx. 6" above nightstands and center them over nightstand tops. I paired the mirrors with a small sequence of 4 timeless prints, center above bed and equal distance from the ceiling to the top of the headboard. You may choose to use the other 2 neutral prints or long horizontal art from the list below instead.

The lighting is all very unique (with in your budget) and mixes materials to really pop off the mirrors and nightstands. Choose your favorites!

The window treatments can be mix matched as well, with 9' ceilings I chose 96" panels, they will graze the floor when you hang them above the window frame. You may use a longer rod so when the panels are not in use they can be pulled fully off to either side and allow maximum sunlight. This will also create a focal point along the window wall and elongate it horizontally.