(Not a Teacher. But a first language Englishman)
Very good I can understand the majority of what you read and it sounds pretty natural. I found a transcript of what you read
"Please call Stella. Ask her to bring these things with her from the store: Six spoons of fresh snow peas, five thick slabs of blue cheese, and maybe a snack for her brother Bob. We also need a small plastic snake and a big toy frog for the kids. She can scoop these things into three red bags, and we will go meet her Wednesday at the train station".
I have underlined those few areas which I couldn't really understand that well. As you can see there aren't that many. Focus on improving these now and it will help you greatly as you learn.
With the words "call", "Stella" and "also" the thing to do is not to rush them. I would say practice them at home by emphasising the "l" sound even if it sounds silly. That way when you use it in normal speech you won't try to emphasise it, hopefully it should just become more clear and natural sounding.
For the word "these" you start the word fine, but it sort of trails off. You pronouce the word "peas" well. "These" should rhyme exactly with "peas" so just combine the two sounds "th" and "eas" together and you should be making a good sounding "these".
Finally, for the word "bags", you just need to add the same ending that you used on the word "peas". So just use the sound after the "ee" sound and tack it on to to the word "bag" which you pronounce well. The sound is a standard BrE "z" and both BrE and AmE use it to start the word "Zuchini" it should not be like the AmE "Zee" sound. Add the sound to the end of what sounds like "bag" at the moment. Make the "z" sound quickly so that the word flows without a break. Again when practicising at home you can over emphasise some of these sounds so that when you use them properly you won't have to emphasise them and they'll flow well.
Student or Learner