Insert and update a row at the same time

I am doing this with Oracle database tables:

I want to insert a row and update the row which was inserted at the same time with a date value.

For example I am comparing two tables and getting a result to a third table.

I am using an insert statement as follows:
insert into table3 (select * from table1 A where not exists (select row1 from table2 B where A.row1=B.row1));

All three tables have same columns. They all have a date column.

Whatever result was coming from the table1 should be updated with todays date in table 3.

The insert statement inserts the value into Table3 but I want to update the date with today's value simultaneously.

Is there a way, please let me know? Thank You for all your help!!

Table 1:

S.No            Date          Name         Phone
1                  11-2-13       abc             123
2                   11-4-12      xyz                456
3                   3-1-11         ghj              498

Table 2:

S.No            Date          Name         Phone
1                  11-2-13       abc             123
2                   11-4-12      xyz                456

result after insert and update on table 3

Table 3:

3                   11-8-2016        ghj              498