setting and using variables in PSQL ????

Hi:

At the PSQL prompt, I want to set some variables based upon query
results, or via static assignment, then insert a record with those
values. Sort of like...

select val1 into x from agedata where name = 'joe_mako';

select val12 into y from sizedata where name = 'joe_mako';

thename := 'joe_mako';

insert into newtable (name, age, height) values (thename,x,y);

Some sort of compound insert statement would solve my problem, but in a
larger sense, how do you (can you ) do something like this inside a
statement blocks of some kind? I've done some PL-pgsql and know about
statement blocks in that context. But I don't want to have to create a
function, use it, then delete it. Was wondering of something else could
be done.

Thanks

-dave