When my 2 month old had a cold...there wasn't too much we could do. Use the bulb suction and the nasal spray to keep the nose moistened and suck out all the gunk. You can also put the humidifier on at night if you are using a heater. It definitely helps. Also, I put mine in her car seat to sleep upright at night for a few days. It seemed to work well with her breathing. You can put the mattress in an upright position in her crib if that's where she's sleeping. Mine is still in her bassinet and I could make it upright because there's not much space, hence the carseat! Hope that helps. Steam from the shower is nice too...not too hot though:)
Don't worry she will get better, and she's building up her little system.