(1) It takes a month for Party A to do it alone, and it takes B months for Party B to do it alone.

( 1/A+ 1/B)* 2 = 1/3

4/A+9/B= 1

Solution: A= 10 months, B= 15 months.

(2) Due to the low construction cost of Team B, Team B needs to go all out 12 months * 65438+ ten thousand yuan =10.20 million yuan (12/15 =/4/5 of the total project quantity completed in 2 months).

10 months later, Team A started working for 2 months and just finished * 200,000 = 400,000.

The total project cost is 6,543,800 yuan+600,000 yuan.