Firstly, Congrats on your coming wedding. Ok, tats the nice part. Now for the advice:

Chinese Ping Kum (dowry but given by groom) is given during the Go Tai Lai. u send betrothal gifts and the angpow together. Normally the in-laws will take a portion and return some of it. This is just a tradition. I'm not sure why you have not heard of it or even prepared for it.
Frankly, if you have not done sufficient study, Google, or at least know the basic stuff for a Chinese wedding, then I think u r not putting enough effort for the wedding. And your love for this future wife of yours is not deep enough. Mayb u need to think it thoroughly if u really want to spend your life with this girl?
I'm in my 30s, all my friends who get married paid the ping kum. Rate is around 5k-20k.
Even though Chinese weddings sound expensive, but most don't fork out tat much after all it ends. Coz the relatives angpow during tea ceremony, wedding dinner covers most of the expenses.
And for those that say it's stupid to have dinner and expect other ppl to pay, u guys miss the point of all this. Receiving a wedding invitation is a blessing and u r there to wish the newly weds lifetime bliss. Most Chinese gave big angpows for wedding coz they r happy for the couple and just want to help out with their expenses.
All in all, if you really love her, sort this out. If you are not tat deeply in love with her, just move on.