It all depends on your engine if its on standard or even overhauled once than ya go for overhaul and if you buy good quality things (its hard to find japanese charade parts but good quality taiwan or korean will be fine) than it should go upto 15 to 17k.
I recently got my Charade's Engine rins and gaskit replaced costed me 7500Rs.
For Swap you should have a good reliable mechanic when my charade's engine was swaped last year we tried 3 different engines even though they seems fine to me but by mechanic was not happy so we kept looking until we found the current one.
Dont go for alterations like putting some other car's engine you wont like the ride if the quality of swap is not good.