If those TONs are locked in your contract you do not have any other option other than having a receiver to withdraw contract's balance. So you need to implement a new operation to withdraw desired amount of TON coins to a specific receptient.
for example:
if (op == op::withdraw()) {
throw_unless(73, equal_slices(sender_address, admin_address));
slice to_address = in_msg_body~load_msg_addr();
int amount = in_msg_body~load_coins();
;; send raw message to "to_address" with specified withdraw "amount"
;; consider reserving some ton coins for storage and future fees
return ();
}