Exclamation [Q] samsung galaxy sgh i 237(it looks likes galaxyexpress)

hi every1 frens plz plz plz help me out to get network.....
I had took second hand Samsung galaxy phone(developer phone)....
it looks like a Samsung galaxy sgh i437 but the stock os is jb 4.2.2 as galaxy express does not have 4.2.2 upgrade yet but in setting I find the name is Samsung galaxy sgh I 237 n baseband as follows i237cuxxxx I searched in internet but derz no clue abt dis phone but the problem is it has very low network frequency it don't connect easily if I m standing down at any sheltar t don't get. network and I think its a developer phone wch was in developing stage...
plz plz help me to get stable network I m using it in India....I tried all network carrier
sry for my poor English
and it ll be appreciated and I ll sure gift him or if necessary I ll pay u...