Anyway, I provided a rough translation. Just a note, đảng means "party", "group" or "gang" but I think "friends" is a better translation in the context of Persona. I don't know what the bottom sign says because half of it is cut off but I think it says something like "...pray for a 1000 years...
I thought the bottom line was something to do with Hanoi's 1000th year anniversary of founding...? I was there at the start of this year... Hanoi, BTW, was founded in 1010.
mừng đất nước = happy country , mừng đảng = happy band , mừng xuân = greeting spring ( or mean happy new year for what is coming soon ) and the bottom " kỷ niệm 1000 năm thăng long hà nội " is 1000th anniversary of Thang Long , Hanoi ( thang long is the name of viet nam in the past )
This is just a coincidence, Persona 4 was released in 2008 but this poster was there in 2006 or earlier. (I'm a Vietnamese) @kazumagvn: Thăng Long was the name of Hà Nội, the capital, Việt Nam name at that time was Đại La.