Air combat on 25.2. 1945

Hello,
For the start I say some short story.
On the 25.februar 1945 was offensive of red army in the direction Detva – Zvolen – Banska Bystrica(In Slovakia – that time Czechoslovakia). Around 14:00h took off two romanian pilots from airfield in Lucenec – adjutant Traian Darjan and capitan Constantin Cantacuzino (They were from 9.fighter group of ARR.). Over Zvolen they found german Fw 190s which were attacking soviet infantry. Constantin Cantacuzino downed one of them. Pilot of machine was gefreiter Hermann Heim from I./SG 2. When they were finding wreck of Fw 190 to confirm vyctory, they lost carefulness and were attacked by german Bf 109s. First downed pilot was Traian Darjan who was victim of german ace from JG 53 Hauptmann Helmut Lipfert. Then was downed Cantacuzino too, but by unknown german pilot.
My questions:
Who downed Cantacuzino?
Where can I find some biographical informations about Hermann Heim?
Where I can found some mission reports from that days?
My last request: If you got any informations, web-sites, books, forums, pictures, photographs, memoirs, contacts or anything other what could help me, please post it here or send there: detvan1945@gmail.com . To pictures or photos I need sources or contact to owners if it is possible.
I will be thankful for any answer.