:(

Since baby is so young I would stay clear of most things.
Ok raise the end of the basket/cot by using a blanket so babies head is slightly raised , this helps baby breath more easily and will help with any mucus.
Having a boiling pan of water perhaps with a small drop of Vicks inside to ventalate the room.
A wet tea towel on a hot radiator works too.
I have used Carvol drops which are good, you put a few drops onto a cloth that you can place near by to baby.
Most of all do not worry baby will soon be on the mend x

To add to the tips from mum2five... if you are breastfeeding you can use a few drops of breastmilk in baby's nose or a few drops of a saline solution and use a nasal aspirator if need be. Might use a humidifier or vaporizer, just be sure they are cleaned well. Sit with baby in a steamy bathroom. Avoid actual decongestant type medications unless baby's doctor prescribes them.
If feeding is a problem because of a stuffy nose, try smaller, but more frequent feeds.

Thanks a lot mum2five. We had baby sitting up a little bit already, but the boiling water in the pan really made the difference.