Great looking pup...
At 11 weeks I would not be concerned...I am certain most of my shep's ears at that age were not standing but I have seen some that have been and even earlier but never mine. A passage from a previous post in the ears section...many many posts in there if you should choose to look...."Between the 5th and 7th month the ear cartilage is still soft enough to encourage the ear into an upright position...."
If it gets to a certain point where you decide to be proactive i.e. taping etc. I had great success with ear forms which are made explicitly for GSDs. Here's a link to the product...if you hunt around you can probably find them cheaper. Ear Supports - $21.99 : Dog Equipment, Police Dog, Schutzhund, Service Dog, Dog Agility
I believe I just used Tear Mender glue to keep them in place.
As far as supplementing a young pup with higher amounts of calcium for promoting the cartilage in the ears, you might read up on it as too much calcium can be somewhat problematic in the young pup's development..i.e. bone spurs etc. I believe I have read the addition of small amounts of vitamin C with the additional calcium keeps the calcium "moving" along in order to prevent problems from an excess of calcium. I have only read this, regarding too much calcium and do not know if it is factual...I assume your vet would be able to guide you on this topic.
I have also read and witnessed this myself with my 3 GSds over the years...IF at any time the pup's ears do come up for short bits the likelihood of the pup's ears standing properly is quite certain. So, since you have seen them up for a short bit at times, that is a good sign for the future.
Enjoy the pup and take plenty more pictures of those floppy ears because it will be a thing of the past before much longer.