Transistors for HK Citation 16

Does anyone know how to obtain or have access to the following transistors or a good working power amp circuit board (?) o/p left channel for my Citation 16 ?
Qty 2 HK# 43031025 RCA 7613
Qty 1 HK# 43025972 Fairchild MPS6543
Qty 8 HK# 43030404 RCA 7629
Any info would be very much appreciated.
Thank You