This is verysimilar but not much cheaper at £75. There was a 20% off promotion for students on the website though - if you're not one, you might know someone who is? Also Phase Eight often seem to have discount codes quite regularly, so you could keep your eyes open for one of those?
Couldn't you buy it and not eat for a few days? If you love it so much and it makes you feel good it seems a shame to miss out. Cuold you ask your parents/husband/brothers/sisters for an early Birthday/Christmas present?
I have tried on that dress and it is absolutely gorgeous! If possible then I would get it if I were you, and then eat beans for the next month! Phase Eight clothes are very good quality and wash very well (in the machine even though they say hand wash!!).
If you still havent bought this yet just wanted to let you know that john lewis have concessions of phase 8 in their stores and they currently have 20% off in a price match promotion, its not on their website as i just looked for you but my friend bought it in store (liverpool) last week for a wedding - and your right it is amazing on, so much that i now want one too!