Insert lines above matching line with content from matching

Shell Programming and Scripting
1

Hi, I have text file:

Name: xyz
Gender: M
Address: "120_B_C; ksilskdj; lsudlfw"
Zip: 20392

Name: KLM
Gender: F
Address: "65_D_F; wnmlsi;lsuod;,...."
Zip:90233

I want to insert 2 new lines before the 'Address: ' line deriving value from this Address line value
The Address value in quotes until the first semi-colon should form the StreetName, and until underscore(_) within this should form the StreetNo,
as shown below

Name: xyz
Gender: M
StreetNo: 120
StreetName: 120_B_C
Address: "120_B_C; ksilskdj; lsudlfw"
Zip: 20392

Name: KLM
Gender: F
StreetNo: 65
StreetName: 65_D_F
Address: "65_D_F; wnmlsi;lsuod;,...."
Zip:90233

Also it would be nice to have the additional check that the code only inserts where the 2 lines (StreetNo, StreetName) are not already available
Thanks,
-sri

2 
awk ' /Address:/ {
        stno = $2;
        gsub(/_.*|\"/,x,stno);
        stnm = $2;
        gsub(/\;.*|\"/,x,stnm);
        $0 = sprintf "StreetNo: %d\nStreetName: %s\n%s", stno, stnm, $0;
}1' file