I don't know of any recruiting agency but you might want to contact Dr. Nazim at the following Australian company, which has many engineering projects in Bangladesh:
SMEC International
South Asia Regional Office Dhaka
House 374, Lane 06, DOHS Baridhare
Dhaka 1206 - BANGLADESH
(Moderated: Please avoid leaving phone numbers on a private forum)
I do not work for SMEC, myself, but I have several friends who do.
Good luck and regards
Chuck Moffitt