Pls. guide me how to get refund of my TDS?

Total salary paid by employer in FY 2007-2008 is 2,50,000
TDS deduction is 8,000

I have following document for 80C rebate
i) LIC(Annual)——————– Rs. 11,000
ii) PPF—————————— Rs. 9,000
iii) Tuition fee for my daughter study in KG is around Rs. 4,000
iv) Donation ————————- Rs. 3,000
Pls. give me in detail how much house rent I can show to get refund of TDS.

Pls. give me detail analysise to get it return back.

how can i investment my money to get maximum refund after 30 years and more?

i m 26 year old man, my family consist of 2 child 1 wife and parents, my daughter is 2 year old and son is 3 year old.
my current salary is 26000 pm. and house hold expenses is nearly 13000 pm.
so how can i invest my money to secure my future. and arrange my childrens marrages in future.
i want to invest my money to the following funds
sip, lic, pension fund, and other as u like.