I purchased my Z5 haswell model with 970m. Now the battery is really sucks can't even last for 30 minutes.

Ran a battery report in Win10, show as below.
DESIGN CAPACITY 52,000 mWh
FULL CHARGE CAPACITY 18,940 mWh

How much for a new battery?
Also I don't want to leave the laptop there, so possible to change it myself (order online and send via post) or go to office to change and get it back on the spot?