Huge pieces- hope you have a large flat. You could use a light green from the rug on the walls, some green pillows on the sofas, and then a pop of another color, such as orange, blue, or similar. See Houzz Photos under "brown sofa" for ideas.

I hate to be rude, and will try to say this as nicely as possible, those sofas and chairs are HUGE and I am surprised that you could not find ones that are more attractive. I know you have paid for them but I would return them and try for something else. They are really unattractive.

Irrelevant unless there is another sofa set out there that is both more attractive and a color that will look great with the green flooring. Grey seems to transition nicely as a neutral upholstery color without being as plain as beige or white. I would not have said this of furniture already in someone's home, but since it is still in the store, perhaps they want to rethink the decision.

To tie the brown and green together, use printed or patterned pillows that contain both colors. Two would be enough. For wall paint, bring home some sample chips after the set is delivered. You can take a tiny clipping of the green carpet fiber and one pillow or arm cover from the sofa set with you when you pick up paint chips. Plan for two or three trips to the paint store, or buy a $25-$50 paint chip fan to save time.

I would suggest keeping the colour of your walls a neutral beige or taupe colour to help compliment the earth tones that you have chosen for this particular space. You can also throw in an accent wall by chosing a wallpaper of your choice to further accentuate the space.
I would bring in multiple decorative pillows of your accent colours, example the green from the carpet and throw in some taupe's and beige's (or whichever colour you decide for the walls) to tie it all together.

A light green wallpaper is a good way to match your green carpet. Put some plants on coffee table. I would choose some white and light grey pillows which can show a sense of natural feeling.

Hi,

To tie your sofa with the rug, you could definitely add green in your toss cushions. Try using a few different shades of green in interesting patterns and textures along with softer shades of taupe and the brown colour of the sofa. It's a large and "chunky" sofa, so be sure to use larger size patterns in the cushions.

For the walls I would stick to a neutral colour and perhaps do a feature wall in one of the shades of green you have chosen.

Good luck!

Fortunate for you brown and cream are so neutral. See what colors you love . Here are some ideas.

Just balance the amount of colors. I'd also keep to solid colors to make your space look bigger. Busy patterns tend to make spaces appear smaller.