Looks like a 10-15 minutes walk on Google maps.
Distance is approx. 2,5 km.
City bus network Goslar
Where you staying is between the bus stops Von-Garßen-Str. and AWO-Sozialzentrum. Both served by the bus line #803 which serves also the Rammelsberg mine.
VRB tariff applies. Goslar is one zone. Single ticket is EUR 1,90. 4 single tickets are EUR 7,60. Mini group (up to 5 persons) day ticket is EUR 8,00.
timetable bus #803
Ah ok, 26 minutes and 2.2 kms accroding to Google maps.