I want to propose to my gf later this year if i can find a suitable ring as soon as possible. All those preparation of the proposal also need some time.

My budget for the proposal ring is around RM 10k. Maybe RM 2 - 3k for wedding bands. My gf is dying for Tiffany & Co and I take some time to think about it since a lot of choices out there that can offer me better ring despite the brand itself. Because i think wedding only once in a lifetime, i think should buy the best for her but if i can get better ring somewhere else then maybe i should reconsider.
I asked my friend last week in KL to help me to see some rings in Tiffany & Co and he told me that it is possible to buy a proposal ring for RM 10k with only 0.25 or 0.3 carat of diamond with Tiffany Setting. I not sure about the colour, cut, etc yet because i not there to see it. Maybe that kind of money can buy you 0.25 carat but low colour and cut which i not really sure yet. I will be going to KL this weekend and I will drop by to see the ring myself.
For the wedding bands, if i able to get Tiffany & Co for the proposal ring, i think to buy the wedding bands in other shops.
So what is your advice on this matter? Should i go for Tiffany & Co or other brand for the proposal ring and how about the wedding bands?
Thanks!