your furniture is muted so play with the colour (am I right in imagining the colour of the emoticons??). I would get an interesting throw and cushions for the couch and keep fresh sunflowers as often as possible too Deep dark red would be fab.
Second choice would be navy (I had bright yellow walls in a hall before and the carpet was navy and they worked great.
Brown and yellow is too 70s for me, Nat & Brittany I reckon you don't have an aversion to it cos you never wore brown dungarees and a mustard yellow polo neck jumper, LOVELY If would post the pic if I could!!! We also had a LOVELY yellow bedspread with brown flowers in nylon on my bed at home for most of my childhood. mmmm Have fun with it!!