Note that in many accents 'give me' becomes 'gimme' in relaxed speech. What we actually hear is more like "Not unless you gi'me another two pound ten shilling towards the dress." The 'v' is not pronounced.

She's speaking so fast that she kind of half says it, half drops it. This is perfectly common in native fast speech. I wouldn't try too hard to listen for words that aren't there or are only half there, it will make you miss the bigger picture. As you have shown you could guess what she said through context, which is what native speakers do anyway, we don't necessarily hear what she's saying, we just have enough knowledge of the language that we can piece it all together, just have you have done. So I'd suggest that you don't try too hard to listen for words that aren't even there, just take meaning from context.

Sorry - in the headline is "speech", of course.