How did you finish 5th with city...?
With that much money every season, you can strenghen your entire back line.
Get Rene Adler or David De Gea to replace given as he is getting old, and Hart just isnt good enough for my liking (though he is superb in real life)
Serge Aurier for right back, and Gareth Bale as a retrained left back, are both two brilliant young players, though you might have to really break the bank to grab Bale.
As for centre backs, i got Ryan Shawcross and Phil Jones as i am managing England and they are both quality young defenders, especially Jones who turns into one of the best in the game in later years.
Finally, i'd recommend bringing in Alexis Sanchez to replace Johnson on the wing as he has contributed a bucket load of assists and goals over the years for me.