D5100 does not have some features like AF, more focus pt etc... But it is sharing the same sensor, so image quality wise same. For tight budget, can get D5100, else D7000. For your budget you can get D7k(S$1600 with kit lens) + Tamron 90mm(S$550) + Kenko extension tube + Tripod + Shutter release cable. everything will come around less than 2.5K. If you buy D5100, you can invest a lot on lens.
Final choice is yours.