The sweater is from Urban Outfitters

Unfortunately, they are all sold out of that exact design online but they have a few left of a different design for $9.99
It might still be available at local stores, so you can always check there.
Here are a few other options from Urban’s online site:

If you’d like a yellow hoodie like the one April wears, you have a couple of options!
I think her exact one is from Urban Outfitters (on sale for $29): they don’t have yellow online at the moment, but you can always check in-store
American Apparel for $48
Old Navy Women’s for $17 and Men’s for $20
Forever21 on sale for $15
H&M (no online link, but they always have them in stores - I got mine for $29)

The shirt April wears in tonight’s episode is available at Urban Outfitters
April wears a Marc Jacobs dress in episode 10 available at Nordstrom’s
The shirt April wears in episode 8 is by Marc Jacobs and is now on sale
April’s dress from the most recent episode
can be purchased here (the original price was $475 but it seems to have been lowered to $285)
April wears a similar camel-colored skirt in season 4 and in NBC’s Brotherhood of Man promo. In the promo she also wears a blue sleeveless blouse. You can get the similar ones at Forever 21.
Skirt: $21.80
Blouse: $13.80