I don't know how to get there by jeep (not really familiar with the route), but I know how to get there by train.
1. From City Hall, try mong pumunta sa pinakamalapit ng train station (I think Central Station). You can walk or you could ride a a jeep.
2. From Central Station, baba ka Doroteo Jose. Lakad ka connection from D. Jose to Recto station.
2.1 You can ride na sa jeep there but make sure na papuntang Sta. Mesa
2.2 Or you can ride from Recto Stn to Legarda Stn.
3. Try to look for Mendiola Peace Arch, aka favorite tambayan ng mga aktibista
You'll see the gate Mendiola Gate to Malacañang
OR, PWEDE KANG MAG-GRAB OR ANGKAS PARA ISANG BIYAHE NA LANG