i will answer you in short for now,
presently, intel have 4 families of mobile processors
core 2 duo
core duo
pentium dual core
celeron m
i have put them in descending order
so it should be clear to you that your 'pentium dual core' is better than a 'celeron m', but fares lower than the 'core 2 duo'
nomenclatute for the 'core 2 duo' > t5xx0 / t7xx0
as also the latest t8x00 & t9x00
'core duo' > t2x00 / t2x50
'pentium dual core' > t2060, t2080, t2130 & t2330
santa rosa is an advanced segment of the 'core 2 duo' family, having 800 mhz fsb
normally 667 mhz & even earlier 'core 2 duo' featured 533 mhz fsb
in short, you have been cheated, if you have paid for a core 2 duo or a santa rosa processor
sure you have the order copy and plz check out the processor number therein & post it, so we can tell you even better
best would be check processor using a small tool,
http://www.cpuid.com/
plz post results
edit:
confusing and seems to have some hickups this cpu-z
terming it as t5200 'core 2 duo'
possibly confusion is because both have similar clock speeds > 1.6 ghz., as also similar fsb > 533 mhz
now, it also mentions it as the intel pentium dual core t2330, which seems to be more apt
socket p > suggest t2330 [t5200 is socket m]
l2 cache is 1024 kb or 1 mb suggesting t2330
[t5200 has l2 cache 2 mb]
find the t2330,
http://en.wikipedia.org/wiki/List_of_Intel_Pentium_Dual-Core_microprocessors#.22Merom-2M.22_.2865_nm.29
& the t5200,
http://en.wikipedia.org/wiki/List_of_Intel_Core_2_microprocessors#.22Merom.22_.28standard-voltage.2C_65_nm.29
sorry for the confusion !