How do I handle this?

My husband's mother came to visit, and to make a long story short, she's not the best mother on the planet. She wanted to take the baby out of his carseat on the freeway because he was crying (thought the seat was unnecessary), she was mad becuase I wouldn't let her give him beans (he just turned 6 months old) & she said that I was way too overprotective and spoiling him (much more happened over a period of 3 days). The final straw came when she was insisting that I picked him up & cuddled him too much. I tried to be diplomatic and said that everyone raises their babies differently, and that he was happy & healthy & I'll pick him up whenever I want to. She physically blocked the doorway to his room and insisted I let him cry. I asked once for her to move and she wouldn't, so I pushed her out of the way. Now she's telling everyone I'm agressive and have issues and that I attacked her. What do I do? BTW, this is was 1st time she's seen the baby since he was born.