You cannot put a 13 SEER heat pump on a 10 SEER coil. You could fiddle around with the flow device and possible get the cooling limping along, and as soon as it switches to heat mode, your compressor will be toast ( liquid slug ).
If the coil is 12 SEER, that may be OK. I would ask the manufacturer of the new heat pump to provide you the match set up...BTU ratings, proabaly a TXV, etc.
Whatever you do, you will normally replace the enitire indoor unit ( air handler, cased coil, whatever). A new 13 SEER coil wont fit inside the old cabinet. They are bigger.