My suggestion is too much brown,obvious don't change the couch. But bring som lighter pillows with some floral pillows maybe teal and brown Walmart has a great collection of those colors. Change the Venetian blinds too more beige and possibly get a small glass table glass to open up and yet you can see the rug.

Remove all of the fake flowers and ''decor'' stuff. It's better to have nothing than to try to fill up the space with inauthentic mementoes. Look to getting some color and pattern into the space. Pillows and rugs can be created or purchased on any budget. Thrift store clothes like sweaters with interesting textural patterns can be crafted into great pillows. The brown blinds are the most problematic element since replacing them really does need to happen, but it will take a pretty good chunk of change to do so. Maybe just diguising them with some drapery panels over them would work for now.

I suggest to add color, to make homey, or black, to make it formal.

Throw pillows are inexpensive and can make a world of difference! Here are a few ideas for you to add color:

http://deciture.com/shop/decor/world-market/emma-throw-pillow/ (floral)

http://deciture.com/shop/decor/wayfair/tommy-bahama-palma-sola-decorative-pillow/ (more contemporary)

http://deciture.com/shop/decor/world-market/red-suzani-embroidered-throw-pillow/

Can you look for curtains in charity/thrift shops? Something not brown. Or paint the walls something cheerful.