Can you help by Step by Step procedure of scammed GT-I9000 topic

Hi
Through this forum(xsenman) I understood my Phone is not Samsung Galaxy S but it is of scammed one (M110S )

recently i had given it to Samsung authorized service center & they tried & in middle the just realized it is not Indian model
So in this process , earlier i was having 2.3.6 but now 2.3.4 Android that to I am facing some problems like Slowness (Internet ON, while Calling, using Alarm etc)

So I decided to upgrade my mobile to 2.3.6 from 2.3.4

but I'm confused as there are different procedure that to very specific one

I am providing complete details about my model can you please provide me guide of step-by-step procedure on how to upgrade
with latest links of software etc (assume I have zero idea on what is ROM & Flashing procedures etc)
But I can do if i have clear guide

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My Model Details:
Firmware Version: 2.3.4
BaseBand Version: I9000ZSJPJ
Kernel Version: 2.6.35.7
Build No: Lidroid-i9000-1.2

Dial *#272*IMEI# , i get blank screen (no Sales Code)
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Dual IMEI numbers (which one to use while upgrading 2.3.4 to 2.3.6 )
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by pressing *#06# i get below IMEI no
354581040087919

by removing battery (back side cover) there is written IMEI no
354581/04/129908/3
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To some extent i went to "repair kit" downloaded files but unable to get proper one from PIT STOP (there are so many versions under each different flavors)

1) Odin3 V 1.70
2) M110S Repair Kit
3) Repair Kit procedure PDF Document ( same as mentioned below)
4) For Latest ROM's kernels and anything else Check PIT STOP

Also Let me know best applications/procedure on to back up data before i do start (what kind of information should be retained )

Thanks &Regards
Raj