You should use a different sterilised bottle each time.
The pump you can use again if you rinse it in clean soapy water after use, and sterilise every 24 hours.
Some people believe you don't need to sterilise bottles/pumps when breastfeeding as the breast milk contents doesn't grow bacteria like formula does because it is "live". I, like you, was more paranoid in the beginning sterilising everything each time, but by about 18 weeks I eased off and only did my pump every 24 hours.
You can add milk to each expressed amount but always go off the date from the first milk you took. You can leave in the back of a cold fridge for up to 8 days. It will separate too- you'll see the 'fatty' cream bit at the top- normal!
I found looking at a slide show of DD on the computer helped. Or expressing on the other boob when she was latched on first thing in the morning when my boobs were solid!
Understandably expressing gives you some freedom to leave baby for a while, but personally it is a faff to do just so your DP can be more "involved". There are so many more things he can be involved in eg bath time, nappy changes, playtime, housework and cooking! 
Has a BF counsellor/GP advised to top up?
Is your dd alert, happy and has plenty of wet nappies?
How many centiles has she dropped since birth?
Congrats on becoming a mum and ebf to 11 weeks, that's good going 