You can use 2 oz Roast Barley.....typical addition for Irish Red. You can also go to an addition of CaraRed if you want to stay German. It will also give you a little head retention. If you want to get a little wild and crazy you can use tart cherry puree....will change the flavor a little but it is what they do at Troggs in PA for their Mad Elf. Also I have heard people talk about using beet juice. Plenty of red there, I've never done it and wonder about flavor although again I have heard that you need to use so little that it does not effect flavor???? If all else fails you can add red food color, it is my understanding that is what Miller/Coors does with their Killians.
OOOps forgot to add that Munich only adds a little red and typicaly that is more of an "amber/red".