Me and my wife are visiting Australia for first time for some family commitments . We are in our early sixties. We are free from January 8th and returning back on January 16, 2018 night to USA. Would be thankful for itinerary suggestions for 7 days and important places to see.. Starting from Melbourne and would love to see Sydney too and any other must see places. Any suggestions much appreciated

7 days is not long so I suggest splitting it roughly between Melbourne and Sydney. Fly between them to save time.
This is peak holiday time for Australia as everyone is on holiday and it will be hot. Make your bookings ASAP.
There is so much to do in Sydney you could spend the 8 days there and not run out of attractions or great day trips.
What about :
Melbourne 2 nights
Fly to Sydney and train to Blue Mountains for 1 night
Sydney 4 nights.
Last time we were in Sydney we stayed at the Oaks Goldsbrough Apartments in Darling Harbour. I liked it there as we got a great view from the apartment.

Thanks

Have a read of Flygirl's post as Bokhara has written a great response about things to do in Sydney. You could probably spend your 7 days in Sydney alone. I like Melbourne but don't rush to go back there. Are you committed to flying into there?

Thanks Tasmangirl.
OP, also see the destination tag here, Australia.com & Sydney.com.au

I know it's not on the same way, but the great ocean road is so beautiful, I recommend to you ! It's the road between Adelaïde and Melbourne : there are a lot of amazing landscapes to see !

Thank you all. Much appreciated. It makes it easier to plan.

GOR - it's peak school holiday time and will be crowded