I'm not going to be much help here, but I'm very interested in hearing responses to this.
I just had acl reconstruction with the hamstring (Nov 30th), and my knee also feels weak, when I walk it sometimes gives way and I'm hoping it's just that the surrounding muscles are still weak.
One month in one would hope it'd be a bit stronger!
Did you find the pain in the knee for bending/straightening goes away? Or has it stayed pretty tight? Every time I try and do my phsyio exercises it's excruciating to go from bending to straightening, and doesn't feel like it's progressing.