On your old computer, go to
C:\Documents and settings\<username> (or
C:\Users\<username> for Vista) and copy the ntuser.dat file somewhere so that you can access it on your new computer.
On your new computer, open regedit.exe, select the HKEY_USERS hive and then go to File->Load hive. Select the ntuser.dat file you got from your old computer, and enter a mount name (doesn't matter what you choose). Go to Software->Patchou-><YourEmailAddress>. All your contact stats are located there. Export that key, and now you'll have to use some find & replace magic on that .reg file before you import it: Open the exported .reg file in Notepad and press Ctrl-H to show to find/replace dialog. In the "find" textbox type "HKEY_USERS\<NameYouUsedToLoadTheHive>" and in the replace textbox enter "HKEY_CURRENT_USER". Save, import, and your stats should be back