Me and wife, both 35

5 room flat: Owes bank 110k, currently valued around 600k
Cash: Combined 270k
Stocks: 130k, yields around 6k dividend a year
Car: Korean, fully paid, left 6 years of COE

Annual income: me, 100k, wife 75k

2 kids.

Any suggestions to grow further? Salary is going to be stuck at this level for a long time. Stock market too high. No money to pay 60% down payment for second property.

This seems to be the same problem many other middle income friends are stuck with.