those who have any advice?

I would like to make a surprise to (surprise) my girlfriend who lives in London .
I understand English well enough well but I have some problem in speaking and writing .

I'm ashamed 'cause her English is fluent.
I wish I could talk to her in English.
She and I ('We' can be used) speak in Italian when we are together .
but I'd like to be able to say something in English.
After summer I will go to London to study and it is also (that's another reason) why I need to improve my English.
London is beautiful and i can't wait to be close to my girlfriend .

those who (Does anybody) have any advice?
how can I learn more (not necessary) faster ?