You can't give her nurofen till she's over 6 months. Have you tried the medicator dummies? Its like a dummy that you can fill with the Panadol and when they suck it comes out. You could also try to sleep her on a slight angle which will help stop congestion and Little Fess is great for her nose if its blocked. Also try the Vicks Baby Balsm. It says from 4 months but you are close enough. If you're still uncomfy with it just put it on her singlet rather then directly on her skin.

That's not all directly related to Panadol lol but Em had a cold when he was only a few weeks old and it was horrible so I completely empathise with you. Hope she's feeling better soon!