Is there anyone to help?

Female assessee having two commercial properties sold as under-

1) COA: Rs 328840 dated 11.01.2008 sold for Rs 450000 on 15.07.2011

2) COA: Rs 120000 dated 17.05.1994 sold for Rs 1460000 on 30.08.2011

and purchased a residential house property in dec 2011 for Rs 1215500

so,

for the 1st property there will be capital loss amounting to Rs 18493 (450000- 328840 * 785/551)

and for the second house property there will be capital gain amounting to Rs 183592 (1460000- 120000*785/259) - (1096293 * 1215500/1460000)  (Is exemption u/s 54F available?)

Are these calculations correct??

And, net capital gain amounting to Rs 165099 be taxed at flat 20% rate or will be aggregated in total income of the assessee?

Please help in the matter as soon as possible.