How do Annie and Helen feel about each other at the end of The Miracle Worker? How is this made clear?

How do the two main characters feel on the final page of one of the most emotional exchanges in a play ever?  For the first time, love exists between them.  Helen is desperately thankful, and Annie is finally in love with her prize pupil.  (This is in direct contrast to earlier in the play where Helen feels only contempt and frustration in regards to Annie.  Annie, in turn, feels no love for this spoiled child.)

Now for the evidence (which is actually very hard to give without relating the entire last scene of the play).  With the help of the water pump and the water, Helen has finally grasped that these finger signs that Annie has been doing over and over again actually stand for the thing she is touching.  Helen begs for more and more before Annie calls for Kate and the Captain.  They clutch her tightly, but then comes some evidence of Helen's new preference for Annie, for Helen wants only to leave their grasp:

Then Helen gropes, feels nothing, turns all around, pulls free, and comes with both hands groping, to find Annie.  She encounters Annie's thighs, Annie kneels to her, Helen's hadn pats Annie's cheek impatiently, points a finger, and waits; and Annie spells into it:  Teacher. (120)

It is not Helen's parents, full of pity, who have opened up this glorious door for Helen.  It is Annie, Helen's teacher.  Helen's parents try to embrace her again, but Helen will have none of it, reaching only for the keys to give to Annie, . . . the very same ones that she stole away at the beginning of the play.  Further, Helen's thanks is expressed in another way, through Kate:

Helen spells a word to her.  Kate comprehends it, their first act of verbal communication, and she can hardly utter the word aloud, in wonder, gratitude, and deprivation; it is a moment in which she simultaneously finds and loses a child.

Kate:  Teacher? (121)

The great love between Annie and Helen finally bursts forth then:

Then she holds out the keys and places them in Annie's hand.  For a moment neither of them moves.  Then Helen slides into Annie's arms, and lifting away her smoked glasses, kisses her on the cheek.  Annie gathers her in. . . . She clutches the child to her, tight this time, not spelling, whispering into her hair. 

Annie:  I, love, Helen.  Forever, and--ever. (122)