Flying only every 2 weeks will not help, you may be better to save up a bit and then do a chunk to start, also, this time of year can be frustrating wx wise so if you waited until about May and saved up for 10-12 hours this would give you a good grounding and the wx would be getting more reliable, you may then need to drop back to your 2 weekly programme but at least you will get a good grounding, if you do this you will then notice the slow down in your progress.
Flying does get cheaper after the licence, for a start you are not paying dual (instructional rates) all the time, but also if you can afford to buy into a group (can be quite cheap with a PFA type and a large group) you will find your costs can come down considerably.