Coco, if a 4rm HDB resale is out of your reach now, why not look at 3rm?
One important thing in buying a resale HDB is you must have patience. You must walk away if it is not within your affordability.
I bought my 3rm resale in Bt Merah area after CNY this year, after viewing more than 40 units over a period of 4-5 months with 3 real estate agents. Good location, corner unit, high floor, near mom's flat, brother's condo and bf's office (If I fall sick he can buy me lunch and dinner haha), as well as overnight parking for non-residents (I realised that this is not the case in some estates, eg, Jln Bt Merah).
When I was asked what my budget for COV was, of course I had an internal figure but I told them it depends on whether the unit is worth the COV asked. I also let them know that I was in contact with at least one other agent. Truly, if they were not interested to entertain me I would be fine. There are plenty of real estate agents in Singapore.
My seller is a nice single lady. We have exchanged contact numbers and for anything I went direct to her, vice versa.