Mavericks messed up the Windows partition

Hello guys, when I was running Mountain Lion I needed more space on my Windows 8.1 partition so I shrank the Mac partition using Disk Utility then used a third party software on windows to expand the Bootcamp partition. And when I installed Mavericks yesterday it seems like the partitions got messed up and I ended up with Windows not being detected at all (no signs of it except "disk0s4" on Disk Utility) then I found a solution suggested by Christopher Murphy suggesting a change of the volume's id to something like 07 then setting it as active (*) and that got Windows back on the boot selection menu (when holding alt key) but still no signs of it on the finder. However, now I'm faced with another problem : when I start Windows, it turns into a black screen and says "Operating system not found"

I desperately tried using a USB Installation drive of Windows 8.1 to repair the problem with the "Startup repair" however it fails. When tried to "refresh the installation" this happens:

which I think means that the recovery tool can't read the Windows partition...

Some users suggested showing results for both of these commands so here are they:

iMac:~ wassgha$ sudo gpt -r -vv show disk0
Password:
gpt show: disk0: mediasize=500107862016; sectorsize=512; blocks=976773168
gpt show: disk0: Suspicious MBR at sector 0
gpt show: disk0: Pri GPT at sector 1
gpt show: disk0: Sec GPT at sector 976773167
      start       size  index  contents
          0          1         MBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34          6         
         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
     409640  482321096      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  482730736    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  484000272  154398192         
  638398464  338374656      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  976773120         15         
  976773135         32         Sec GPT table
  976773167          1         Sec GPT header
iMac:~ wassgha$ sudo fdisk /dev/disk0
Disk: /dev/disk0 geometry: 60801/255/63 [976773168 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
 2: AF 1023 254  63 - 1023 254  63 [    409640 -  482321096] HFS+        
 3: AB 1023 254  63 - 1023 254  63 [ 482730736 -    1269536] Darwin Boot 
*4: 07 1023 254  63 - 1023 254  63 [ 638398464 -  338374656] HPFS/QNX/AUX

and looking at the results, we can clearly see a gap between the "Darwin Boot" and the Windows partition (409640 + 482321096 does equal 482730736 but 482730736 + 1269536 which should be 484000272 and that's where the windows partition should start, is shown as 638398464 so there's a gap of 154398192 bytes that should contain the boot manager and a lot of necessary Windows files...)

Can someone please help me? I'd do anything to get my Windows partition back without loss of files... The files are important to me and I was stupid not to back up...