Dear Niki,
1) Sec 54 - It is not necessary that new House should be in the name of the assessee. [But this doesn't hold good in case of Sec 54F]
Purchase’ does not mean that the new house must be registered in assessee’s name - For the purpose of attracting the provisions of section 54, it is not necessary that the assessee should become the owner of the property purchased. The word ‘purchase’ occurring in section 54(1) has to be given its common meaning, viz., buy for a price or equivalent of price by payment in kind or adjustment towards a debt or for other monetary consideration. Therefore, for the purpose of applicability of section 54, registration of the document is not imperative - Balraj v. CIT (Delhi).
2) Computation is correct provided u din't forget to indexed the COA {In addition to this COI & Expenses on Transfer can also be deducted}