Lots and lots of choices my friend and depends on the kind of money you're willing to spend and/or you have relatives travelling from US/Canada that can bring you things (ordered online 3-4kg). If getting it internationally isn't an option, then the local choices get a bit limited and details below.
Light colors specifically white is one of the toughest colors to pop. It needs to be without its paleness (which you've gotten rid of) but slight off coloring will keep coming back and you'll need to use a cleaner wax (e.g. Meg white wax) every 4-5 months. I believe you already have Meguiars ultimate wax (which is the best in meguiars range and locally abundantly available). In Megs professional range you have M21 but if you already have Ultimate wax, you wont really notice much difference on a white with M21.
White color (to my eyes) gives best looks when they produce a glassy feeling. Sealants are known to give reflective/glassy look and One of the best superior/durable sealants for white color is the Klasse/CarLack/Werkstat arcylic range, something I've personally used and loved and is an all time favorite in the intl detailing community. I saw DC selling Carlack range (nano improved version of Klasse). Other options are Wolfgang sealant 3.0, Autofinesse Power seal Or tough coat (all top quality sealants).
If you want to take it to another next level (an extra 10-20% for the white more %age for other darker/warmer/metallic colors), then you should add natural wax and you could get Dodo white diamond OR Dodo light fantastic. The Autofinesse and dodo ranges are available from Ahmad bhai.
So,
Sealants:
- Autofinesse power seal OR tough coat (contact @ahmad_yar )
- Carlack (dont have idea how much its being sold at at DC, check @vague_one )
- Wolfgang sealant 3.0 (contact @Aerojet )
Natural wax (contact Ahmad bhai for all three below):
- Dodo white diamond
- Dodo light fantastic
- autofinesse temptation
In your scenario and with a limited budget, stick with Meguiars ultimate wax (that you already have) and get yourself a natural wax (I would suggest Dodo white diamond). With dodo range you have the option of getting yourself a panel pot so you could get a taste of product without breaking an arm and leg. It is however a proven product, so no risk associated if you go for the bigger pot (better value for money per oz).
If you're going to try a different sealant, then opt for the sealants in above range i mentioned.
Hope this helps...