Can you correct this, please? :)

L'Aquila, 8 July 2015

Dear Laura,
How are you? So much time has passed (it has been so long) since you left for London! You are so lucky...I've never been to London but I'd love to. How long are you going to stay there? If I remember well, you told me that you wanted to stay in London for three months...is it that right? However, If I were you, I'd be staying as much time long as possible. I was told London is a beautiful city...Have you visited anything yet(what have you visited/where have you been)? Are you having the time of your life?

As far as my holiday is concerned, well, it's not the greatest sort one can imagine. I'm staying with my friends here, in L'Aquila; at times it's really pleasant (above all when you relaxing or going out with them) but at other times, everything seems so boring to me! As you know, L'Aquila is a mountain town and spending the whole summer without the sea is indescribably terrible (above all to me, who was having been born in a seaside town!!)
I'm really looking forward to visiting my parents and coming back home!

By the way, some days ago I read in a local paper that a travel agency organizes a trip to Pesaro ( the trip will take place in October). The main topic of the trip is Gioacchino Rossini, the well-known composer who was born in this that city in 1792; and guess what! People under 25 pay only 30 Euros. It's a great bargain if you consider that you're leaving (by coach) at 6 a.m from L'Aquila; then, when you're arriving, you're having lunch at a restaurant near the Rossini museum (the birthplace of the composer). After visiting the museum, you'll have a few hours to go sightseeing. I think it's a good bargain.
Tell me what your opinion about it is.
Looking forward to your reply,

yours Cristina

P.S. Could you buy a souvenir for me,please? Do not forget to tell me how London is like...I'm so curious!

Notes: Using And at the start of a sentence is bad grammar. I've outlined some comments in blue brackets, that are some suggestions to improve your fluency.