OPERROR INVOLVING ACR X AND ACR Z.

Narrative

I HAD JUST ASSUMED THE DUTIES OF THE W FINAL/E FINAL RADAR POS COMBINED TOGETHER. THE TWR SUPVR INFORMED ME THAT ACR X HAD JUST MISSED APCH OFF OF RWY 23R AND WAS HDG 360 DEGS AND LEVEL AT 2000 FT. I WAS MODERATELY BUSY SEQUENCING TFC TO RWYS 23R AND 23L. I NOTICED VFR HELI TFC BEING WORKED BY THE N DEP RADAR CTLR THAT WAS CLBING THROUGH 1800 FT AND CONVERGING WITH ACR X. THE APPROX DISTANCE BTWN THE ACFT WAS 1 - 1 1/2 MI. NOT KNOWING THE HELI'S INTENTIONS AND NOT HAVING TIME TO COORDINATE WITH N DEP CTLR; I TOLD ACR X TO CLB IMMEDIATELY TO 3000 FT AND TURN R TO 050 DEGS. AS IT TURNED OUT; THE N DEP CTLR HAD INSTRUCTED THE HELI TO CLB TO 2500 FT TO MAKE A TRANSITION OVER THE ARPT. THE MAJOR PROB OCCURRED WHEN I CLBED ACR X TO 3000 FT AND ANOTHER ACFT; ACR Z; WAS IN THE SAME AREA AT 3000 FT ALSO. WHEN I REALIZED THAT MY ACFT WAS CLOSE TO ANOTHER; I TURNED MINE TO 090 DEGS TO DIVERGE AWAY FROM THE OTHER WHO WAS HDG 050 DEGS. THE MAIN FACTOR CAUSING THIS ERROR; IN MY OPINION; WAS MY FAILURE TO COORDINATE WITH N DEP PRIOR TO CLBING. MY IMMEDIATE CONCERN WAS THAT ACR X AND THE HELI WERE GOING TO COLLIDE. I SHOULD NOT HAVE CLBED PRIOR TO COORDINATING. THIS ERROR OCCURRED WITHIN 1 MIN OF ASSUMING DUTIES WHICH SHOULD BE A LESSON TO BE VERY CAREFUL ABOUT WHAT ACTIONS ONE TAKES BEFORE BECOMING SETTLED INTO THE POS.