Good job realizing you want to do things differently for your daughter. Here are some things that helped me. We only had one tv (none in bedrooms). Then, we limited it to a certain amount of time per day. Basically, doctors have been saying for 30 years that children under the age of 2 should watch no tv - it seems to lead to shorter attention spans. Pediatricians have a campaign of 'less than 2 hours per day of any electronics for all children'. So, I found it helpful to use it only as a silver bullet - when I needed it to get dinner on the table, for example. So, 5-6pm or whatever time that is for you. Then I wasn't trying to quit cold turkey (which we know doesn't work for dieting), but was also giving myself parameters.
It takes time to retrain oneself to 'relax' in a different way. Just like we don't want our children to be trained that when they are hurt, a cookie makes them feel better, because it inculcates a habit of feeding sadness, in the same way, we need to teach (mostly by example! so hard) our children how to relax in healthy ways - a book, a puzzle, some beautiful music.
Children also love routine. not necessarily rigid, but knowing an order for the day. I had a playdate scheduled pretty much every day. At 20 weeks, she is still napping or having quiet time in her crib for 1-2 hours, so that is good nap time for you, too - in your own room. I found that if I gave my child undivided attention for 30 minutes, then I could expect her to entertain herself with her toys for 20 minutes so I could get some things done. If I put my child off, trying to get stuff done, she was more clingy and demanding - so starting off with some play time worked well.
wake, breakfast, play, clean up (she plays), you clean up together (she can help put her toys back), play date with 10am snack, home for lunch, play, she plays while you do a chore, nap, snack, play, she plays, tv while you get things done, dinner, family time, bed.
In the evening after dinner and before bedtime, we went on a walk (in Michigan winters - 20 was warm) every evening. That way the kids were occupied in a stroller and we could talk a bit.
We went to the library once a week for story time and brought home 20 books. So, reading daily is a great way to spend time. Just take 20 books home - you will realize what books you like and fine tune it over time. Illustrations are really important b/c she is looking at them - so make sure there is beauty in both illustration and language. Don't worry about things being over her head - children love to hear language. Mother Goose nursery rhymes are great. I stayed away from obnoxious, farting, boogers, etc - b/c I don't think children need help being grose - but they do need help learning to be kind, compassionate, helpful, sacrificial and other oriented. I'd have my child on my lap and she could help turn the page. It was okay if I didn't read each word and I'd ask a question about what she saw in the picture.
Other things to do are have a CD on and sing the songs. Libraries also have tons of music. Pandora is great online, because it will choose music for you based on your interest. I don't know if you can choose Raffi... Ballet music is great because most girls love the sound and they think their mom is beautiful and graceful no matter what!
And it is great to set up playdates where you drop her off or have another child over. I found that 1.5 hours was enough time at that age and that I had to be present - I couldn't expect to get anything done during that time. The kids are happy, you get a break or the mom gets a break, and you build community by depending on each other. Ask someone to watch your child while you go to your OB appt. - and watch that person's child while the mom relaxes with coffee with another woman - no kids! - or goes grocery shopping.
I have found that being a SAHM does not mean I need to be home much and it certainly doesn't mean I need to be home alone with my child!
Congrats on number 2